Objective and subjective assessment of selected factors of the work environment of forest harvesters and forwarders

Abstract

This article was aimed at assessment of selected factors of the work environment, which influenced the operators of harvesters and forwarders. The selection of the work environment factors was based on a thorough literature survey. From the survey exposure to whole-body vibrations, noise (equivalent and peak), microclimatic conditions and mental load were selected for detailed observations. The measurements were conducted according to international standards and assessed according to European or national legislation. Subjective assessment of the effects of the work environment was conducted through a structured interview. The exposure to whole-body vibrations was 0.5 m·s -2 . The equivalent noise exposure was 78 dB, peak noise exposure was 130 dB. The average temperature inside the machine cabs was 17.9°C and average airflow velocity was 0.06 m·s -2 . Mental load was high according to the Meister questionnaire, three operators considered the load inadequate, two considered it adequate. Subjective assessment showed that operators considered other factors to be light or no load.Keywords: noise exposure; whole-body vibrations; microclimate; mental load Work environment is a set of all conditions in which workers carry out their work. It consists of all workers and factors present at the workplace, or of those who have to do with the work and influence the health or comfort of workers. The worker is exposed to many harmful factors which interact and their joint effect can be synergistic or complementary (Schwartz et al. 2013).Operators of multi-operational machinery carry out their tasks in ergonomically designed cabs capable of partial attenuation of noise and vibrations caused by the machine movement, driving gear, and working parts of the machine. Cabs are also equipped with air conditioning and glare reducing windows. Some factors (e.g. electromagnetic, ionising radiation, various chemical factors, or energy expenditure) do not apply to the jobs of multioperational machinery operators. Their assessment would only consume time with no significant effect on the overall outcome of the assessment. The nature of work in mechanized logging partially shifted from physical to mental after employment of multi-operational machinery. The need for muscular activity decreased and the need to stay concentrated and alert through long periods grew in importance. Harvester operators have to be able to process a lot of information, react quickly, and retain their concentration in monotonous, repetitive operations (Axelsson, Pontén 1990;Poschen 1993;Gellerstedt 1997;Gellestedt et al. 1999;Tsioras 2012). Operating the machines is quite demanding. According to Gellerstedt (2002), 4,000 control inputs per hour have to be carried out by the operator, due to the lack of automatic functions of the boom and harvester head. Despite the ergonomic design of the cabs, the operators of mobile machinery are exposed mainly to noise (Hans-

Proposal for an Ergonomic Conformity Index for Evaluation of Harvesters and Forwarders

“…These values were similar to those found by Jankovský et al (2016). The high vibration value caused the FW1 to obtain the lowest ECI between the analyzed machines.…”

Análise da exposição à vibração de corpo inteiro em harvesters de esteiras e pneus na operação de desbaste

“…Jankovsky et al [4], realizaram um estudo para avaliar ergonomicamente o ambiente de trabalho de operadores de harvester e forwarder e, dentre as máquinas avaliadas, 3 eram harvesters e 2 Forwarders, ambos com rodados de pneus na colheita de pinus. Os autores identificaram valores de aren médios em 0,46m/s², valor próximo ao encontrado nesse estudo.…”

“…Para a seleção dos fatores a serem estudados, os autores realizaram uma pesquisa bibliográfica, na qual identificaram a exposição ocupacional à vibração como fator relevante para o estudo. Os autores identificaram níveis médios de vibração em 0,46m/s² [4].…”

“…Os limites e recomendações acerca da exposição às vibrações estão previstos em normas internacionais, as quais servem de referência para a legislação nacional pertinente ao assunto [4].…”

Analyzing Online Videos: A Complement to Field Studies in Remote Locations

“…well as supervising the machine's operations [15,27]. A study shows that the cognitive workload in operating a forest harvester is comparably similar to operating a fighter plane [4].…”