Clothing insulation and temperature layer and mass of clothing under comfortable environmental conditions

摘要

This study was designed to investigate the relationship between the microclimate temperature and clothing insulation (Icl) under comfortable environmental conditions. In total, 20 subjects (13 women, 7 men) took part in this study. Four environmental temperatures were chosen: 14°C (to represent March/April), 25°C (May/June), 29°C (July/August), and 23°C (September/October). Wind speed (0.14ms^-1) and humidity (45%) were held constant. Clothing microclimate temperatures were measured at the chest (Tchest) and on the interscapular region (Tscapular). Clothing temperature of the innermost layer (Tinnermost) was measured on this layer 30 mm above the centre of the left breast. Subjects were free to choose the clothing that offered them thermal comfort under each environmental condition. We found the following results. 1) All clothing factors except the number of lower clothing layers (Llower), showed differences between the different environmental conditions (P<0.05). The ranges of Tchest were 31.6 to 33.5°C and 32.2 to 33.4°C in Tscapular. The range of Tinnermost was 28.6 to 32.0°C. The range of the upper clothing layers (Lupper) and total clothing mass (Mtotal) was 1.1 to 3.2 layers and 473 to 1659 g respectively. The range of Icl was 0.78 to 2.10 clo. 2) Post hoc analyses showed that analysis of Tinnermost produced the same results as for that of Icl. Likewise, the analysis of Lupper produced the same result as the analysis of the number of total layers (Ltotal) within an outfit. 3) Air temperature (ta) had positive relationships with T_chest and T_scapular and with T_innermost but had inverse correlations with I_cl, M_total, L_upper and L_total. T_chest, T_scapular, and T_innermost increased as t_a rose. 4) I_cl had inverse relationships with T_chest and T_innermost, but positive relationships with M_total, L_upper and L_total. I_cl could be estimated by M_total, L_upper, and T_scapular using a multivariate linear regression model. 5) L_upper had positive relationships with I_cl and M_total, but L_lower did not. Subjects hardly changed L_lower under environmental comfort conditions between March and October. This indicates that each of the T_chest, M_total, and L_upper was a factor in predicting I_cl. T_innermost might also be a more influential factor than the clothing microclimate temperature.