[Comparison of formulas for calculating average skin temperature and their characteristics]

In order to obtain data of skin temperatures experiments were carried out using three healthy young Japanese males. The subjects were exposed to each of the four environments with dry bulb temperatures of 15 degrees C, 19 degrees C, 25 degrees C and 33 degrees C. At each of these air temperatures, relative humidity and air movement were set at 50% and 0.15m/s respectively. The subjects wore only athletic shorts, seated on the meshed chair. Each subject was measured with thermisters continuously for one hour under these conditions to obtain twenty-nine regional skin temperature. The above experiments were made with one subject at a time in the test chamber. The data of skin temperatures observed were substituted into twenty-eight different weighting formulas for comparison. The present analysis revealed that the calculation from the 12-point and the 7-point skin area formulas by Hardy-DuBois showed approximate mean values of the twenty eight. Moreover, the values calculated from the formula by Nadel et al, which was weighted by skin area and thermal sensitivity, are similar to the values calculated by the formula of Mochida, which was weighted by skin area, heat transfer coefficients and thermal sensitivity. Furthermore, the authors verified that the area-mean weighting factor was derived from the Teichner's definition in which a limiting value of arithmetical mean of skin temperatures gave a value of average skin temperature.