Measuring instruments or their parts can only be verified, if they are type approved or passed a conformity assessment procedure. The type approval is the procedure measuring instruments have to pass to be accepted for verification unless they are not subject to a European directive according to the new approach (MID and directive on non-automatic weighing instruments).
Type approved are only measuring instruments or their parts with a physical basis and technical design which assure their correctness and reliability at least for the relevant period of subsequent verification.
A national approval can be a general, a special or an exceptional one.
Measuring instruments for which approval by notice is not stipulated in the verification regulations are generally approved for verification. In practice this applies only for a few simple mechanical measuring instruments. For a special approval a notice is issued. Thus the conformity of the type with statutory requirements is certified. Measuring instruments not completely complying with the verification regulations or for which no verification regulations have been issued can be approved for verification only exceptionally.
The special and exceptional type approval of measuring instruments or their parts is based on the result of a detailed physico-technical examination which usually is carried out by the Physico-technical Testing Service (PTP) of the BEV. The type approval ordinance stipulates the types of national approvals as well as EC-type examinations of measuring instruments, the application for approval, the approval procedure, the notice on approval, regulation for the period of validity of the approval, suspension and expiration of type approval and national as well as EEC-approval markings and stamps.
At the European level EEC-approvals according to the “old approach” are distinguished from EC-type approvals or EC-type examination according to the “new approach” of the European Union. In these cases no national approvals are granted. At the European level the conformity of the type with an EU-directive is assessed.