To be or not to be comfortable: basis and prediction

Abstract

Abstract This chapter presents how human thermal influences are at the origin of thermal sensation, and (dis) comfort. It is generally admitted that a negative or positive heat balance will induce a cold or warm sensation, respectively, and the ISO standard stipulates that these sensations will be associated with thermal discomfort. In addition to the need for clarifying the way discomfort is defined and assessed, this chapter insists on the fact that comfort or discomfort are not simple notions, it states that some lacks of information still exist and it emphasizes the major roles played by the various body areas and their interactions. Global discomfort may be found for conditions under which no clear sensations are perceived. This chapter supports the idea that an adequate computer model is appropriate to determine the risks of discomfort based on the hypothesis that thermal comfort results from the integration of all the thermal inputs related to local thermal deviations from an optimal body cartography. Some examples, derived from human experimental results, illustrate the validity of this model when all environmental and local effects are considered, especially local thermal insulation due to clothing distribution.