This standard describes the method for determining the Shore A and D hardness of elastomers and plastic materials by means of two types of durometer with different indenter. 2 Shore hardnesses are quantities of an empirical nature and are mainly used for current checks. For elastomers it is recommended to use the hardness measurement in international grades according to UNI 7318-74 and UNI 7319-74. 3 Shore A hardness applies to less rigid materials and is determined with a type A durometer, having a truncated cone indenter: Shore D hardness applies to more rigid materials and is determined with a type D durometer, having a rounded conical indenter. Both hardnesses are expressed with an empirical graduation ranging from 0 to 100. Shore A hardness must not be used above the value of 90. Shore D hardness must not be used below the value of 30.
UNI 4916-1974 history
1974UNI 4916-1974 Testing of elastic materials and plastic materials. ShoreA and D hardness determination