Effect of thermal radiation from fabrics on human body

The effectiveness of the far infrared radiation processing cloth as clothing material is discussed. Temperature rise of the irradiation plane is more rapid than the heating by heat conduction and convection for the radiant heating. Skin temperature change and thermal sensation of the examinee wearing the sweater with a plastic heater at back were examined. “The relation of the inverse proportion of heat intensity to the time needed until the extent of thermal stimulation perceived was examined. Individual examinees tested, by oral contact, the extent of the pleasant sensation produced by the warming condition. They judged the extent of the warming according to whether it felt comfortable. Individually, they differed a great extent in their opinion of what was comfortable. However, for all examinees, the relationship of warming and feeling comfortable was confined within narrow parameters. In this experiment, a unit of the radiant heat stimulation was determined by dividing mW/cm² by the warming period, since intermittent warming was carried out.” The degree of the skin temperature perceived by the sensation was almost fixed at 33–35, even if the radiant heat strength differed. The rapid thermal stimulation by radiant heating can be perceived even for a slight temperature rise of the skin. It is also necessary to consider the temperature rise speed, except for the temperature rise of the cloth surface, when the effectiveness of the far infrared radiation processing cloth was discussed.