Heat stress, thermal comfort and control strategy in a warm-humid workplace.

Abstract

The purpose of this study was to design a local ventilation system (LVS) to help reduce the moisture content of a Scalder hall, evaluate its comfort and thermal stress before and after implementation of LVS and introduce an appropriate index to evaluate warm and humid workplaces. The design of the LVS was performed according to the ACGIH standard (VS-30-01). Heat stress and thermal comfort assessment were performed before and after LVS using humidity index (Humidex), discomfort index (DI), heat index (HI), wet-bulb globe temperature (WBGT) and predicted mean vote index (PMV) indices and the results were compared with predicted mean vote index-predicted percentage of dissatisfied (PMV-PPD) subjective indices. The results of heat stress parameters showed that LVS was able to reduce relative humidity (RH) and wet temperature (t_nw) by 47% and 7 ° C, respectively. This has caused subjects to feel the heat from hot and very RH hot to warm and the hot and percentage of dissatisfaction has dropped by more than 70%. Design and implementation of a LVS reduced the ambient t_nw by decreasing RH. Results also showed in warm and humid workplaces, DI index are highly correlated with subjective evaluation of thermal comfort and this index can be used to evaluate the thermal conditions of the workplaces.