The standard of ISO 11092 uses the sweating guarded hotplate method, the skin model method, to simulate the heat and moisture transfer process close to the human skin, and to test the thermal resistance and water vapor resistance of textiles under steady-state conditions to evaluate the comfort of textiles.
This standard specifies methods for the measurement of the thermal resistance and water-vapour resistance, under steady-state conditions, of e.g. fabrics, films, coatings, foams and leather, including multilayer assemblies, for use in clothing, quilts, sleeping bags, upholstery and similar textile or textile-like products.
Textiles -- Physiological effects -- Measurement of thermal and water-vapour resistance under steady-state conditions.The test fabric is placed on the surface of a porous metal plate.
The plate is heated and water is channeled into the metal plate, simulating perspiration. The plate is then kept at a constant temperature.As water vapor passes through the plate and the fabric, it causes Evaporative Heat Loss and therefore more energy is needed to keep the plate at a constant temperature.
Ret is the measurement of the resistance to evaporative heat loss. The lower the Ret value, the less resistance to moisture transfer and therefore higher breathability.
