Extract from the (German) Measurement and Calibration (Weights and Measures) Act, as amended 23 February 1992, Art. 2, Compulsory Calibration and Other Measures to Ensure the Reliability of Measurement
Art. 2 Paragraph 1
Measuring instruments for business or official usage, for traffic systems, health protection, labour protection or radiation protection must be approved and calibrated if required, to guarantee the accuracy of measurement.
Art. 2 Paragraph 4
The calibration is, [...], carried out by the responsible authority and by state-approved testing centres for electricity, gas and heat measuring instruments (official calibration). The calibration of new measuring instruments according to these regulations can be carried out by the manufacturer (calibration by the manufacturer).
Art. 25 Continuation of the mandatory calibration
It is forbidden to employ, or to have ready for employment without special preparations being made prior to use, uncalibrated measuring instruments for determining length, area, volume, weight or thermal and electrical energy, in the course of business usage.
Excerpts from the German calibration regulations, dated 12.8.1988
Art. 12 General information
Paragraph 1 The validity of the calibration is restricted to two years, unless otherwise stated in this section or in appendix B.
Paragraph 2 The Federal office can fix a shorter validation period for a limited or restricted type-approval. This is not valid for the European type-approval which is limited to ten years.
Paragraph 3 If the validity of the calibration is less than one year, the validity of the calibration commences at the end of the calendar year in which the measuring instrument was last calibrated. By a late re-calibration, within three months of the begin of the new calendar year, the period of validity is as intended for the original calibration.
Art. 14 Extension of validity
If the correctness of the measuring instrument is proven during a random check, the validity of the calibration is extended according to periods of time laid down in appendix B. The random checks must be made according to the procedures named in appendix B.
Art. 77 Interim regulations
Paragraph 9 The calibration validity of cold water meters calibrated before 1st January 1993 according to appendix B no.6.1., apart from the cold water meter according to clause 2, expires at the latest on 31st. of December 1998. The calibration validity of cold water meters used for cost distribution of the amount of water measured by a domestic water meter, which was calibrated before 1st January 1993, expires on 31st December 2000. The calibration validity of positive displacement gas meters calibrated before 1st January 1993 according to appendix B. no.7.1., expires at the latest on 31st. of December 2000. Article 14 remains unaffected.