A data base for determining the effect of walking on clothing insulation

The purpose of this study was (1) to provide a balanced data base for determining the effect of body motion on the insulation value of indoor clothing ensembles, (2) to develop equations from the physical properties of the garments and their component fabrics for predicting the dynamic insulation, and (3) to develop equations from standing insulation values and walking speeds for predicting the change in the insulation due to body motion. The insulation values of 24 different types of indoor clothing ensembles were measured on a movable thermal manikin in an environmental chamber. To determine the maximum change in clothing insulation during body motion, a walking activity which made all four limbs move was used. The difference in the insulation value between walking at 90 steps/min (3.70 km/h) and not walking at all (i.e., standing) was compared. In addition, four different walking speeds--30, 50, 70, 90 steps/min--were used with three representative ensembles to evaluate the effect of walking speed on the insulation value. For an empirical prediction of the change in the insulation value of indoor clothing due to walking, selected physical characteristics of textiles and clothing were measured. Textile variables included fabric thickness, weight, air permeability, stiffness, and insulation value. The outermost layer of each ensemble was area weighted and used for the prediction. Clothing variables included the amount of body surface area covered by clothing, ensemble weight without shoes, the area of the garment openings, and the air volume enclosed in the clothing ensemble.; Regression analyses were conducted to provide the equations for predicting the change in insulation due to body motion. The results indicated that the stationary manikin insulation value explained 65% of the variance in the change of insulation due to walking: Absolute change in I{dollar}sb{lcub}rm cl{rcub}{dollar}, clo = (0.394 {dollar}times{dollar} ICLSTAND, clo) + 0.002. Some combinations of textile and clothing variables explained up to 94% of the change in I{dollar}sb{lcub}rm cl{rcub}{dollar} due to walking. When the effect of walking speed and the standing insulation value were combined, these variables accounted for 94% of the variance in clothing insulation: Absolute change in I{dollar}sb{lcub}rm cl{rcub}{dollar}, clo = (0.504 {dollar}times{dollar} ICLSTAND, clo) + (0.00281 {dollar}times{dollar} WALKSPEED, steps/min) {dollar}-{dollar} 0.240.