Calibration is the metrological test used tocheck, calibrate and certify measuring instruments that can be calibrated. During calibration, the metrological properties of the measuring instrument to be calibrated are compared with reference or measurement standards of the Physikalisch-Technische Bundesanstalt(PTB).
In addition to the Physikalisch-Technische Bundesanstalt, only verification offices and approved testing laboratories are permitted to perform verification. The latter two institutions are subject to the sovereignty of the federal states and are supervised by the verification authority.
Verification is regulated by the German Verification Act (EichG) - Gesetz über das Mess- und Eichwesen. This stipulates that calibration and its inspection may only be carried out by the Physikalisch-Technische Bundesanstalt and the relevant calibration authorities. The calibration itself is legally binding depending on the area of application, for example, for measuring instruments that are used for business purposes. Calibration is carried out at certain intervals to determine whether the measuring instrument meets its metrological characteristics and whether the measurement deviations comply with the permissible deviations of the calibration regulations. If the metrological requirements are met, this is documented with a calibration certificate.