SAFETY-ORIENTED MULTI-TASK APPROACH TO MANAGE WHOLE-BODY VIBRATION EXPOSURE AMONG QUARRY OPERATORS

摘要

The oscillation generated by external and internal forces is one of the principal characteristics of machinery. The impulses are transmitted to workers' bodies through the part in contact with the vibrational surface, such as the steering wheel of a machine (known as "hand arm vibration" (HAV)), contact surface or the driver's seat of a machine (known as "whole-body vibration" (WBV)). These represent an occupational issue that can generate adverse health effects, annoyance or simple discomfort for the workers during their daily activities. Biodynamic responses of the human body to WBV are reported in terms of the driving point mechanical impedance and apparent mass, transmissibility and the power absorbed by the body. The most common WBV occupational exposure is represented by the operator seated in a variety of vehicle categories such as cars, buses, forklifts, tractors, trucks, and heavy machinery either on or off paved roads in different work contexts. Previous studies investigated the power absorbed by the human body during daily exposure and the consequent potential negative effects on the human health. They evidenced that health effects are connected to the intensity of the vibration levels. In order to reduce workers' exposure, an efficient method could consist of analysing the power frequency spectrum. In fact it provides relevant indications in order to adopt the correct preventative or corrective measurements such as specific suspended seats, extra breaks and individual work schedules. This study is aimed at assessing the WBV exposure among drivers of machinery in a quarrying context thus proving a useful tool to manage such a risk in terms of work organization and scheduling.