Daily vibration exposure in forestry: the difference between manual and motor-manual cleaning methods

SAŽETAK: Problem izloženosti štetnim vibracijama u šumarstvu javlja se s primjenom prvih motornih pila u sječi i izradi. Iako je rad s motornim pilama bio višestruko brži, produktivniji te fizički manje zahtjevan od ručnog obaranja, motorne pile emitirale su velike količine vibracija i s vremenom je došlo do negativnog utjecaja na zdravlje šumskih radnika. Bolest bijelih prstiju (Raynaudov sindrom) postala je stvaran problem s velikim potencijalom za smanjenje radne sposobnosti radnika. Uz primjenu motornih pila, u šumarstvu se za neke radove i dalje upotrebljavaju ručni alati. Glavna tema ovog rada je usporedba dnevne izloženosti vibracijama u uzgojnim radovima čišćenja pri radu s motornom pilom i kosirom. EU Direktiva 2002/44/EC nedvosmisleno propisuje granične vrijednosti za dnevnu izloženost vibracijama, A(8) koje služe kao mjera protiv pretjeranog izlaganja vibracijama. U ovome radu procijenjene su A(8) vrijednosti za rad s motornom pilom i rad s kosirom u čišćenju. Vremenski udjeli pojedinih radnih zahvata u radu čišćenja dobiveni su korištenjem metoda studije rada i vremena na videosnimkama efektivnog rada. Rezultat vremenske analize rada je da radnik pri radu s motornom pilom 46,7 % vremena provede u radu rezanja, dok se ostatak vremena odnosi na različite načine nošenja upaljene motorne pile. U radu s kosirom radnik prosječno napravi 27 sjekova u minuti. Razine vibracija su snimljene vibrometrom Brüel & Kjaer 4447 i izračunate prema uputama ISO 5349 norme. Dobivene su A(8) vrijednosti od 4,9 m/s2 na desnoj ruci i 3,4 m/s2 na lijevoj ruci pri radu s motornom pilom te 13,7 m/s2 na desnoj ruci pri radu s kosirom. Rezultati upućuju na ozbiljnu zabludu pri organiziranju rada i korištenju ljudskih resursa. Uvriježeno mišljenje da je rad s kosirom, na koji se radnici s narušenim zdravljem većinom alociraju, “lakši” od rada s motornom pilom, može dovesti do ozbiljnih zdravstvenih posljedica za zdravlje radnika. Rezultati ovoga istraživanja indiciraju na smjer kojim se šumarska struka treba voditi pri organiziranju uzgojnih radova čišćenja koji će biti u skladu s važećim propisima zaštite zdravlja radnika.The problem of exposure to harmful vibrations in forestry arises with the use of the first chainsaws in logging and construction. Although working with chainsaws was many times faster, more productive, and physically less demanding than manual felling, chainsaws emitted large amounts of vibration and over time had a negative impact on the health of forest workers. White finger disease (Raynaud\u27s syndrome) has become a real problem with great potential for reducing workers\u27 working ability. Along with the use of chainsaws, some operations still require hand tools in forestry. The main theme of this paper is to compare daily vibration exposure in cleaning operations when operating a chainsaw and billhook. EU Directive 2002/44/EC clearly establishes limit values for daily vibration exposure, A(8), which serve as a measure against excessive vibration exposure. In this paper, the A(8) values for working with a chainsaw and working with a billhook in cleaning are estimated. The timeshares of individual cleaning operations were obtained using time study methods on videos of effective work. The result of the time analysis indicates that the worker spends 46.7% of his time in cutting, while the rest of the time is spent in different ways of carrying a chainsaw. In working with the billhook, the worker makes an average of 27 cuts per minute. Vibration levels were recorded with a Brüel & Kjaer 4447 vibrometer and calculated according to ISO 5349 standards. A(8) values of 4.9 m/s2 on the right hand and 3.4 m/s2 on the left hand when operating the chainsaw were obtained, and 13.7 m/s2 on the right hand when operating the billhook. The results point to a serious misconception when organizing work and using human resources. The common belief that working with a billhook, to which workers with disabilities are mostly allocated, is "easier" than working with a chainsaw and can have serious health consequences for the health of workers. The results of this study indicate the direction in which the forestry profession should be guided in organizing cleaning operations that will comply with the applicable regulations for the protection of the health of workers