Vibration levels and daily vibration exposure while using different tools in a forest cleaning

Abstract

Forest cleaning, being an operation that requires investment, but the return on investment is due for the next generations, utilizes tools and methods that mostly haven’t been humanized. Harmful vibration is still present in today’s forestry operations, and new tools provide possible reduction of exposure to vibrations. Petrol chainsaw and battery chainsaw (late cleaning) and billhook, machete, and battery shears (early cleaning) were used and observed in this study. Vibration levels were measured and assessed using validated Brüel & Kjær 4447 vibrometer which complies with the ISO 8041:2017 standard. The measurement was performed according to the recommendations of ISO 5349-1:2001 and ISO 5349-2:2001 standards. Vibration exposure was assesed using work sampling method on the obtained video recordings in order to calculate relative shares of different work elements. Results show that hand tools (machete and billhook) are causing the highest vibration levels, while battery shears cause the lowest. Battery chainsaw causes higher vibration levels while cutting, but lower daily vibration exposure than petrol chainsaw. A detailed revision in the classification of tools is needed, considering their ability to produce and transmit harmful vibrations to the operator. Using the current classification, the daily exposure to vibration of workers in early forest cleaning is high above legislative values.

Forestry Ergonomics Publications in the Last Decade: A Review

“…These operations still require motor-manual or even manual tools involving a high proportion of manual labor [71]. Logically, these operations are subjected to substantial risk factors such as postural load [52], workload [72], noise [3], and vibration [10] and the forestry research community took an interest in them, especially in Brazil, Canada, and Indonesia (Figures A1 and A2).…”

“…Vibration, especially hand-arm vibration (HAV), is viewed as a risk factor that can only be mitigated via shorter exposure time through the likes of job rotation, limited working time, or entire harvesting system replacement. HAVs in forestry are generated from hand-held and hand-guided tools and machines like chainsaws, brushcutters, stump grinders, billhooks, machetes, axes, and sickles [10]. Long exposures can cause problems with blood circulation in fingertips and damage to muscles, nerves, and tendons [28].…”

“…Lately, many studies regarding vibrations have been performed on battery-powered chainsaws; the general conclusion is that hand-arm vibrations are weaker than those of similar power and weight-class petrol chainsaws [10,35,36]. Different hand tools used in forest cleaning are deemed unsafe because of high hand-arm vibrations [10]. Chainsaw vibrations, i.e., daily vibration exposure, are not affected by the years in use of the chainsaw [37,38].…”

“…Risk factors included in forestry ergonomics publications are substantial and their dynamic appearance is observed in this review. Regardless of time period or harvesting systems, "traditional" risk factors like noise [3][4][5][6][7], vibration [8][9][10][11], and workload [12][13][14]…”

The Magnitude of Fatigue Recorded in Individual Body Parts of Chainsaw Operators after Work

“…Chainsaw operators are also exposed to negative physical, psychological and environmental factors due to working outdoors and the frequent use of both hand tools and machines [24]. These factors also include the impact of vibration [25,26], noise [27], dust [28], fumes [29], unnatural and uncomfortable working positions [30] and the risk of musculoskeletal disorders (MSDs).…”