A heat weathering system was constructed to measure the heat transfer properties of textile materials. All experimental condition such as heating, cooling and thermal stability of the environment were controlled by a microcomputer. Some applications of this system were described.
　An explanation of the heat transfer phenomena was given in relation to the surface contact between a sample and a heat source, the humidity of the sample and the structure of knitted fabrics. The results were as follows.
　1) Heat loss passing through a sample was always proportional to the temperature difference between the high heat source and low heat source even in the non-continuum material such as a fiber assembly.
　2) The heat transfer of the fiber assembly increased with increasing the compressive force. The heat transfer properties were determined under a non-stressed condition.
　3) The heat flow associated with the convection were determined as a function of the temperature difference in this system.
　4) The effect of the extended fabric on the heat flow, which was not detected by the steady method, was obtained by observing the transient response time of the heat source.

DESCENTE SPORTS SCIENCE Vol.9/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE