Evaluation of Change in Air Gap Underneath the Garment for Various Pro-Longed Body Postures Using 3D Body Scanning Emel MERT *1,2 , Agnes PSIKUTA 1 , Marie-Ange BUENO 2 , René M. ROSSI 1 1 Laboratory for Protection and Physiology, Empa – Swiss Federal Laboratories for Materials Science and Technology, St. Gallen, Switzerland 2 Univ. Haute Alsace, Laboratoire de Physique et Mécanique Textiles, Ecole Nationale Supèrieure d’Ingénieurs Haute Alsace, Mulhouse, France http://dx.doi.org/10.15221/14.210 Abstract Heat and mass transfer through the garment on wearer’s body is affected by the change in the air gap thickness and the contact area more than by the material of the fabric. For thermally relevant evaluation of the thermal properties of clothing, e.g. during work or leisure time, it is important to analyse the air gap thickness and the contact area for prolonged, stationary and ergonomically correct body postures. A flexible manikin, which has similar body size and flexibility of joints as an adult male, was used to mimic realistic human body postures (standing and driving). To obtain accurate and reliable 3D scans, stands with fixations and the garment with easy openings were designed and Artec MHT 3D scanner was used. The presented study indicates that the distribution of air gap thickness and contact area between the body and the garment was depended on the posture of human body due to the gravitational force and the pressure from the chair on the flexible garment. The results of this study can contribute to an improvement of clothing design for functional garments and can be applied to heat and mass transfer modelling in clothing for various postures. Keywords: air gap, contact area, 3D body scanning, prolonged postures, heat and mass transfer. 1. Introduction People’s expectation towards variety of clothing is to ensure a protection against harsh environmental conditions and thermal comfort [1]. This can be provided by maintaining balanced heat and mass transfer between the clothed body and its environment. The heat exchange processes in the clothing are affected by the change in the air gap thickness and the contact area more than by the material of the fabric. The thermal properties of the air layer are related to its size, which, in turn, depends on the form of the wearer’s body (morphology, posture and the movement) [2], the mechanical properties of the fabric (fabric stiffness and shear resulting in fabric drapability), and garment design and size [3, 4]. Since the heat loss rate through the garment depends mostly on the shape and the thickness of air gap and the magnitude of the contact area between the human skin and the garment, it is important to accurately determine these parameters for variety of scenarios. The stagnant air beneath and on the garment is an effective insulator against to heat and mass transfer in a prolonged body posture. Different methods have been used to evaluate the air gap volume using gas trace method [4-6], cylindrical mathematical method [8], three dimensional (3D) body scanning [9]. These methods contributed to overall evaluation of air gap and its thermal effect. However, there is only scarce information on local distribution of air layer and contact area and their effect on the heat and mass transfer through the garment. Therefore, further development has been done to evaluate local distribution of air gap thickness [3] and contact area between the body and the garment [10]. These studies offered an overview of the local distribution of air gap thickness and contact area over the body parts and are helpful for mathematical clothing modelling. However, the manikins used in these studies had an artificial standing straight position, which is ergonomically suited only for a short time. For thermally relevant evaluation of the thermal properties of clothing e.g. during work or leisure time, it is important to analyse the air gap thickness and the contact area for prolonged, stationary and ergonomically correct body postures. The aim of this study is to accurately analyse the change in the distribution of air gap thickness and the contact area between human body and the garment due to various prolonged body postures using 3D scanning. A flexible manikin, which has similar body sizes and flexibility of joints of an adult male, *Lerchenfeldstrasse 5, CH-9014 St. Gallen, Tel: +41 58 765 76 62 email: emel.mert@empa.ch 5th International Conference on 3D Body Scanning Technologies, Lugano, Switzerland, 21-22 October 2014 - 210 -