A Review of Some Significant Research Trends in Thermo Physiological Comfort of Fabrics to Suit Varied Areas of Applications and Weather Conditions
Kavitha S and Gokarneshan N
Published on: 2019-11-25
The article critically reviews some significant trends attempted in enhancing the thermal comfort of fabrics. One attempt has been directed towards providing protective clothing for workers in harsh weather conditions of extreme cold climate. It aimed to determine how the people working in cold harsh climatic regions protect themselves against cold and the sufficiency, and the selection criteria of the garments. Basic thermal insulation of the reported clothing has been estimated. The thermal insulation of the clothing has been measured by thermal manikin [standing/walking]. It has been found that the thermal insulation of the selected clothing was on an average 1.2 and 1.5 in mild cold [−5 to +5°C] and dry cold [−20 to −10°C] conditions, respectively. The findings revealed that workers selected their clothing based on occupational [time outdoors], environmental [temperature, wind, moisture] and individual [cold sensitivity, general health]. A special design of clothing based on ‘sombrero-effect’ by inclined wedge providing shadow on the base material has been proposed and investigated analytically to improve the thermo physiological comfort under dry and hot environment. The analysis of the heat and mass transfer in the proposed design enables numerical prediction of cooling heat flow at the skin surface level. It is observed that the analytical framework of heat and mass transfer is able to give useful results. A pressure-relieving mattress has been developed along with multilayered functional bed cover to reduce the magnitude, direction and or duration of pressure and temperature, thereby avoiding excessive tissue distortion on vulnerable parts of the body. The interface pressure and temperature between body and mattress are measured and analyzed using the parameters, such as the deformation index and pressure gradient. The pressure-relieving mattress developed reduces the interface pressure by 30-60% and reduces the pressure by about 3oC. Hence, the new mattress developed along with the cover reduces the chance for pressure ulcer formation and improves the comfort of the patients. In yet another interesting research, a study of indexes characterizing thermal comfort of garments has been outlined and a new so-called wet comfort index of sport dresses and underwear at real conditions of their use have been presented. The maximum value 1 indicates the best Thermo physiological comfort level in the wet state. It is found that for best sport dresses consisting of special polyester and polypropylene surface grooved fibers, the wet comfort index does not exceed 0.2. This surprisingly low level demonstrates the importance of testing of thermal comfort properties of fabrics in wet state by means of special instruments.