DIN 53505

German standard for determining the Shore hardness of rubber and plastics using a durometer — functionally equivalent to ASTM D2240 but with a key procedural difference: DIN 53505 specifies a 3-second reading time (versus 1 second per ASTM D2240). This difference matters because rubber continues to deform under the durometer indenter after initial contact, so a 3-second reading typically gives a value 1-3 Shore A points lower than a 1-second reading on the same specimen. When comparing hardness values, always note which standard was used. Test conditions: specimen minimum 6 mm thick, flat surface, 23±2°C, minimum 5 readings averaged. DIN 53505 is referenced in European and many Latin American rubber specifications, particularly for products manufactured to DIN or EN standards. ISO 48-4 (the international equivalent) specifies methods for both IRHD (International Rubber Hardness Degrees — a more precise micro-hardness test) and Shore methods, referencing 3-second reading. For commercial specifications, stating "60±5 Shore A per ASTM D2240 or DIN 53505" covers both standards. Per DIN 53505:2000-08.