An index for evaluation of human thermal response in hot and moderate environments

The research about the evaluation of human exposure to thermal environments has been performed for a long time, nowadays making available many indices allowing us to do a complete and refined evaluation. Shortly, the followed approaches are of the two types: that one based on empirically obtained indices (WBGT, Effective Temperature etc.) and the rational one, based on human body heat balance and thermoregulatory response evaluation (PMV-PPD, New Effective Temperature, HSI, Required Sweat Rate index etc.). Really and as a general rule, the field of application of these indices is limited to the evaluation of thermal comfort or alternatively of heat stress, being so required to use different indices for stress or comfort, not existing a single index for an evaluation in both cases. Starting from these premises the authors propose a method for evaluating human thermal exposure with two main goals: to be used also outdoor, thus taking into account direct and not direct thermal effects of solar radiation, and to allow both the evaluation of thermal comfort and stress exposure (as required), even if with a little greater approximation than that one obtained by using the single indices.