Thermal insulation provided by chairs with various clothing ensembles

The thermal insulation provided by chairs significantly influences human thermal comfort. On the one hand, it modifies the heat exchange mechanism at the contact points between the body and the chair surface. On the other hand, an increase in local thermal insulation can exacerbate differences in thermal insulation across various areas of the body, impacting overall comfort. However, the thermal insulation data for chairs are decades old and thus need to be updated to reflect modern designs and materials. Six typical office chairs were tested using a thermal manikin dressed in five typical clothing ensembles (ranging from summer to winter). The effective thermal insulation of the chairs varied between 0.04 and 0.14 clo when tested in the nude. The added values ranged from 0.04 to 0.30 clo when tested with different clothing ensembles. Higher clothing levels correspond to higher added chair thermal insulation. Therefore, a simple weighing method was developed to adjust the seasonal coefficient of the mean chair insulation value (0.75 in summer, 1.0 in transition, and 1.25 in winter). Furthermore, a simple model was established for calculating the overall clothing level for a seated person. The model was validated using data measured in this experiment and other external sources, with a minimum prediction mean error of 1.4 %. This study provides a reference for accurately acquiring the thermal insulation value of chairs for a seated person in thermal comfort studies.