Experimental investigation on physiological and perceptual thermal responses through simulated hot-humid deep mine conditions

Abstract

Miners in underground space often experience discomfort and heat strain due to combination of hot-humid environment and strenuous physical intensity. To investigate the impacts of manipulated variables, amounts of trials were conducted in a controlled climate chamber, with air temperatures of 29 °C and 32 °C, air velocities of 0.8 m/s and 1.8 m/s, and labor intensities of 3 km/h and 5 km/h, respectively. The physiological responses of mean skin temperature (Tmsk), oral temperature (Tor), sweat loss (SW), and heart rate (HR) were measured during these trials, along with the perceptual responses of thermal sensation vote, thermal comfort vote, thermal satisfaction vote, thermal acceptability vote, air movement expectation vote. The results indicate that Tmsk, Tor, SW and HR exhibit an upward trend in response to increasing air temperature and labor intensity, but decrease with rising air velocity. Tmsk and Tor are primarily affected by air temperature, while SW and HR are predominantly influenced by labor intensity. Notably, increased air temperature and labor intensity have negative effects on perceptual sensations, whereas augmentation in air velocity can marginally mitigate perceptual sensations. Tmsk and sweating rate exhibit the potential to serve as an indicator for evaluating and forecasting perceptual sensation. Tmsk values of 36 °C and 35 °C can be identified as the maximum thresholds for miners' thermally acceptable and comfortable skin temperatures. The findings can provide valuable references for understanding thermal responses of individuals in hot-humid deep mine conditions, and establish a robust basis for promoting working safety and comfort of miners.