Thermal comfort and physiological responses with standing and treadmill workstations in summer

Abstract

The study investigates human thermal comfort requirements when using standing and treadmill workstations. Twenty-eight subjects were exposed to four ambient temperatures (20, 23, 26, 29 °C) while conducting four activities (sitting, standing, walking at 1.0 km/h, and walking at 2.0 km/h). Physiological responses, including metabolic rate, skin temperature, and skin wettedness, were measured continuously, while subjective thermal comfort responses were surveyed. Treadmill workstation significantly increased human metabolic levels and reduced the associated environmental neutral temperatures. Using linear regressions, the predicted neutral temperatures are 24.3 °C (sitting), 23.3 (standing), 22.2 (walking 1 km/h), and 21.1 °C (walking 2 km/h), respectively. The 80% acceptable temperature range varied from 20.5 to 28.2 °C for sitting and standing, 20.0–26.9 °C for walking 1 km/h, and 17.6–26 °C for walking 2 km/h. PMV-PPD model was not able to predict human comfort accurately when using standing or treadmill workstations. Based on our findings, a temperature zone ranging from 20.5 to 26 °C is seen to satisfy the summer thermal requirements for over 80% occupants in a space containing a combination of sitting, standing, and treadmill workstations. However, providing personal comfort control would be necessary, given the substantial inter-individual differences.