Requirements concerning the manufacturing, placing in the market and entry into service of measuring instruments have mainly been harmonised in the economic area of the EU. Requirements concerning the most common measuring instruments have been described in EU directives.
In the New Approach directives, harmonisation is comprehensive in that for measuring instruments that are monitored under law, the directives set out essential technical requirements that the instruments must meet. These New Approach directives must be followed, if there are requirements concerning measuring instruments in the national legislation, but no other requirements shall be set.
Compliance with the Old Approach directives is voluntary: it is possible to set other requirements for measuring instruments, but it is not possible to prevent measuring instruments from entering into the market if they have the EU approval.
Measures associated with scheduled inspections of measuring instruments do not fall under the scope of the directives, even if virtually all Member States have rules to that effect.