Thermal Conduction Effects in Human Skin. I. Experimental Data Acquisition

To determine the maximum permissible temperature any material may attain without causing pain or burn on contact with bare skin, over 2000 observations were made of pain threshold during contact with materials at elevated temperatures. Six materials were used representing the full range of thermal properties of good conductors to good insulators. Initial specimen and skin temperatures, interface material-skin temperatures throughout contact, and time to pain threshold were noted. An orderly relationship was found between pain threshold and material temperature, either longer exposures or higher specimen temperatures being associated with better insulative properties. Variations in thickness of the epidermis affect these times and temperatures so that families of curves are generated from data obtained at sites of increasing thickness. On the basis of the relationship demonstrated between pain sensation and thermal properties the material temperature which will cause a blister on contact may be predicted.