The influence of clothing distribution and local discomfort on the assessment of global thermal comfort

A field study was carried out in a hypermarket located in Southern Italy in order to evaluate the environmental comfort in large-scale retail trade buildings. Global and local thermal comfort conditions were studied by collecting exposure data and subjective responses of employees using both questionnaires and simultaneous physical measurements. In a few cases discrepancies appeared between subjective ratings and the corresponding PMV-index, suggesting that the latter could be unable to reliably estimate thermal comfort when clothing insulation is unevenly distributed on human body. Analysis of collected data confirmed this, with particular reference to female workers wearing skirts. In addition, such effects may be further emphasized by local thermal discomfort, which may finally influence global thermal perception. Analysis of the results showed that cold floor and radiant temperature asymmetry caused by warm ceiling played a major role in emphasizing the negative effects due to uneven clothing distribution, confirming that this particular combination of events may bias PMV model accuracy.