Development of a Device for Measuring Heat-Moisture Transfer Properties of Apparel Fabrics

A new device has been developed to measure the heat transfer properties of apparel fabrics and is reported in this paper with some examples of an application of this device. The basic functions of this device are as follows : (1) Detection of the heat absorption by a fabric ; This absorption starts just after the touching of a thin copper plate containing an amount of heat on the surface of fabric. The signal of the heat flow associated with this absorption passes a low pass filter, then the peak value of the heat flow which is defined as qmax appears at about 0.2 sec. after the touching and recorded to evaluate the fabric properties relating with warm/cool feeling of fabric touch. The thermal conductivity and diffusivity of fabric are also measured by this transient method.(2) Quick measurement of the fabric thermal conductivity by a steady method ; A thin aluminium heat plate is used as one of two plates of the parallel plates method. The plate temperature is controlled precisely with the high-speed response. The plate temperature follows within 10 sec. with a stepwise command of 2°C. This quick response enables the measurement of the thermal conductivity without making any disturbance on the state of fabric such as fabric moisture-regain change during measurement.(3) Thermal insulation measurement by various modes ; The heat loss through fabric into the air is measured and recorded continuously. The ordinary method of the fabric thermal-insulation testing, referred to “dry method”in this paper, is completed within a few minutes by this new device. As one of the testing variation, the skin method is presented. A paper containing a lot of water is placed on the heat plate to simulate human skin and a fabric sample is put on this paper or with a moderate space of gap between a fabric and the paper.The heat loss measurement of this system provides much information about heat-moisture transfer behavior of fabrics. For example, it is clearly shown that wool summer suitings are much cooler than polyester summer suitings.Some of these results are described in detail.