Human response and productivity in hot environments with directed thermal radiation

The thermal environment is a major factor affecting workers’ health and productivity. Its influence is more evident in environments with high temperatures and humidity accompanied by high thermal radiation. Thus, it is important to understand human response and productivity in hot environments with directed thermal radiation (DTR) in order to improve the working conditions and protect laborers. Therefore, studies on environments involving high temperatures and humidity with DTR should be emphasized. In this regard, an experiment to investigate the effect of DTR and labor intensity on human bodies was conducted in a climate chamber, and three radiation intensities (0.0 kW/m2, 1.0 kW/m2, 2.0 kW/m2) and two labor intensities (4.5 km/h, 6.0 km/h) were selected as experimental conditions. Physiological parameters (core temperature, skin temperature, heart rate and sweat loss) and psychological parameters (comprehensive thermal sensation and fatigue feeling) of 30 subjects were collected during the experiment. Paired t-test and analysis of variance (ANOVA) were used to analyze the corresponding experimental data. The results of this study indicated that most of human physiological parameters and subjective feelings are affected by temperature and humidity, and also by DTR and labor intensity. Specifically, high-intensity radiation significantly affects oral temperature, skin temperature, heat rate, and sweat loss. However, labor has no effect on skin temperature. Furthermore, this study shows that physical productivity is affected by labor and high-intensity radiation. However, mental productivity is solely affected by radiation. These results are expected to serve as preliminary data supporting the establishment of reasonable working times and intensity as well as the control of working environment.