IRHD = International Rubber Hardness Degree
The International Rubber Hardness Degree according DIN ISO 48 – Part 1 is, beside the Shore hardness, another test method for the measurement of the rubber hardness. IRHD shows the resistance of a rubber specimen against the intrusion of a ball with a diameter of 2.5 or 5.0 mm respectively under a defined pressure.
We differentiate between sub-ranges soft and normal.
If the rubber products are very small you can apply the IRHD measurement according DIN ISO 48 – Part 2. You will use a small ball with a diameter of 0.4 mm.
|Sub range||IRHD range||Diameter measuring ball||Specimen thickness|
|soft||from 10 to 35 IRHD||5,0 mm||10-12 mm|
|normal||more than 35 IRHD||2,5 mm||6 bis 10 mm|
|IRHD normal||from 35 to 90 IRHD||0,4 mm||1,5 bis 2,5 mm|
The standard test specimens are platens with plat, parallel top and bottom surfaces.