ISO 16859-2 is the ISO standard that specifies methods for direct and indirect verification of instruments used to determine Leeb hardness in accordance with ISO 16859-1. It also describes when each type of verification is to be performed. The current edition is ISO 16859-2:2015, which ISO confirmed in 2026.
Direct verification checks that individual instrument performance parameters fall within specified limits. Indirect verification uses hardness measurements on reference test blocks calibrated to ISO 16859-3 to check the overall performance of the instrument when testing in the direction of gravity. The indirect method can also be used on its own for periodic performance checks in service, which suits routine checks of portable instruments between full verifications.
Portable rebound testers such as the NG-LeebGen 3000 portable Leeb hardness tester are used for Leeb testing where verification to ISO 16859-2 is part of the lab or field routine. If you need help matching ISO 16859-2 requirements to your parts or setup, contact our team.
