Comparison of Hand-Arm Vibration Levels Between a Chainsaw, Weed Eater, and Backpack Blower

1742 

Student Poster 

C Boyd¹, J Oh²

¹UAB School of Public Health, Mountain Brook, AL, ²UAB School of Public Health, Birmingham , AL

Charles Boyd  
UAB School of Public Health

Jonghwa Oh  
UAB School of Public Health

Weed Eaters, Chainsaws, and Blowers are commonly used in grounds maintenance and forestry industries. Despite the large presence of such occupations in the US, occupational exposure assessment of hand-arm vibration (HAV) has been often focused on the source evaluation (i.e., tools), not human exposure. In this study, we examined HAV exposure levels experienced by the operators of a chainsaw, weed eater, and backpack blower. To do this, operations of the tools were simulated in controlled laboratory conditions and palm-strapped vibration dosimeters were worn on the hands of the operators in order to obtain exposure data. This data will give a better picture of HAV exposure levels that could be affecting forestry, landscaping and groundskeeping workers in Alabama, and throughout the nation. The operation of a weed eater resulted in the highest vibration levels, ahv, followed by a chainsaw and a backpack blower, regardless of an operator.

Many workers in forestry and groundskeeping industries use vibrating hand-held tools on a regular basis. Long-term, intense exposure to hand-arm vibration (HAV) can lead to vascular, neurological, and musculoskeletal health effects, collectively known as hand-arm vibration syndrome (HAVS). One of the most common symptoms is vibration induced white finger (VWF). Studies have suggested that prevalence of VWF anywhere from 80-100%, while in warm climates the prevalence is only estimated to be 0-5%. However, a dose-response relationship between vibration exposure and HAVS in warm environment has not been fully understood. The purpose of this study was to examine the vibration exposure levels when operating a weed eater, chainsaw and backpack blower. HAV exposure levels was evaluated with wearable palm dosimeters to better represent actual exposure to the tool operators. The study results will be used as the basis for our follow-up, prospective studies in which the correlation between the vibration magnitude and HAVS in warm environments will be examined.

Two researchers alternatively simulated the operations of the power tools by changing roles, i.e., study operator and subject (UAB IRB approval obtained). For a weed eater, the head of the tool was swung side to side in an approximately 30" swing, with every swing lasting approximately 1 to 1.5 seconds. For a blower, the nozzle of the tool was swung side to side, similarly to a weed eater. For a chainsaw, hard wood (oak and poplar) was cut into slices. Accelerometer inserted palm adaptors of vibration dosimeters (SV103, Svantek, Warszawa, Poland) were worn on both hands of the subject during the simulation to collect triaxial acceleration data. Each experiment was performed for five minutes and for each tool type, experiment was triplicated and the vibration total values (ahv) were averaged.

Results: Average vibration total values (ahv) of a subject 1 were 3.250 and3.449 m/s2, and of a subject 2 were 2.685 and 3.315 m/s2, for the right and left hand, respectively, during chainsaw operation. During blower operation, average ahv of a subject 1 were 1.149 and 0.160 m/s2 and of subject 2 were 2.053 and 0.194 m/s2, for the right and left hand, respectively. Average ahv of a subject 1 were 5.116 and 3.483 m/s2, for the right and left hand, respectively, during weed eater operation. Average ahv of a subject 2 were 5.877 and 4.396 m/s2 for the right and left hand, respectively, during weed eater operation. The operation of a weed eater resulted in the highest vibration levels, ahv, followed by a chainsaw and a backpack blower, regardless of an operator. Consistently higher ahv were observed in the right-hand sampling data, regardless of the type of tools used and operator.

Conclusions: Higher vibration magnitude, i.e., ahv, in the right hand could be due to the tool design and operator skill. No conclusive pattern in ahv between operators was observed: operator 1 had higher ahv when operating a chainsaw while operator 2 had higher ahv when operating a weed eater and blower. Further investigations on the effects of individual factors (e.g., hand force and posture) and work-related factors (e.g., operation time) on the vibration magnitude are needed.

Exposure Assessment Strategies

Sampling and Analysis