Thermal environment in freight transport - the case of a vehicle without air conditioning

Abstract

The thermal environment in the workplace is decisive in creating the optimal conditions and maximizing the productivity of the workers. The value of the different environmental variables such as temperature, radiant heat, relative humidity and individual variables (such as metabolism and clothing) are determinants to evaluate the thermal stress exposure of workers during their daily activity. The objective of the current study is to evaluate the occupational exposure to the thermal environment of a heavy goods vehicle driver, motivated by frequent complaints, such as the difficulty of sleeping in the vehicle with high temperatures during the day. To determine the conditions to which the driver is exposed, the globe temperature, dry and wet bulb temperatures, as well as the air velocity inside the vehicle were measured, considering both the work and the rest situation. In addition, the metabolism related to physical activity and the thermal insulation conferred by clothing were also determined. Once the parameters were obtained, Professor Malchaire's Excel (R) sheet was used for obtaining the values for the Wet Bulb Globe Temperature (WBGT) index, which were above the occupational exposure limit values (ISO 7243). Results point to a hot work environment where thermal stress is liable for the dissatisfaction of workers. The need to act on thermal stress is imperative, preferably through the implementation of engineering and organizational protection measures that can improve the workplace. The need to establishment of a legislation set to address this particular issue was also an outcome of this work.