Water vapor or sweat resistance test

A human skin – the skin or the sweating hot plate , determines the water vapor resistance of fabrics. The skin model is represented by a 20 cm × 20 cm porous plate of sintered stainless steel and by electrical heating the porous plate temperature is maintained at human skin temperature of 350C . This porous plate is completely covered by the fabric to be tested.25 

A guard ring is also heated to the same temperature as porous plate , which prevents heat loss at the sides and underneath , so that the amount of heat given up by the measuring head can only flow through test sample as shown in following diagram :

Underneath the porous plate , the head contains engraved channel along which distilled water is supplied, which is vaporized through the porous plate. In this way , sweating of human skin is stimulated. The skin model is placed in a climatic chamber where air temperature, moisture content and air velocity over the sample fabric is maintained. Sweating resistance or water vapor resistance of fabric sample can be determined by :