Inspecting measuring instruments

METAS and the cantonal enforcement authorities are responsible for inspecting legally regulated measuring instruments used in Switzerland and the Principality of Liechtenstein. The aim is to ensure that measuring instruments have the necessary measurement reliability and quality and meet the legal requirements.

Measuring instruments that are already on the market and are subject to legal regulations are inspected to ensure correct measurements. These inspections are carried out by METAS and the cantonal verification offices. In this way, it contributes to consumer protection and fair trade, as well as to the health and safety of people and the environment.

Legally regulated measuring instruments are subject to a three-stage control system consisting of:

  • Market surveillance
  • Testing of measurement stability
  • Review

Market monitoring of measuring instruments

Market surveillance ensures that measuring instruments which are placed on the market in Switzerland and the EU comply with the statutory requirements in accordance with the conformity assessment procedures carried out.

In Switzerland and the Principality of Liechtenstein, METAS is responsible for monitoring the measuring instruments market and implements this in cooperation with the cantonal verification offices. These enforcement authorities check whether manufacturers, importers and other distributors comply with the applicable requirements and check measuring instruments manufactured in Switzerland as well as imported from the EU or third countries.

Market monitoring takes the form of random checks or on the basis of justified indications that a measuring instrument does not comply with the regulations.

Testing of measurement stability

Throughout the entire duration of use, the responsible enforcement bodies (METAS and cantonal verification offices) regularly check whether the measuring instruments retain their metrological properties.

The possible procedures for maintaining the measuring stability of measuring instruments are regulated in Annex 7 of the Measuring Instruments Ordinance (Measuring Instruments Ordinance, SR 941.210). The measuring instrument-specific ordinances of the Federal Department of Justice and Police (FDJP) specify which test procedures can be used for the individual measuring instrument categories and at what intervals they take place.

The procedures for maintaining measurement stability ensure, among other things, that:

  • correct measurement results are displayed and billed, for example when measuring electricity, fuel gas quantities and thermal energy. Energy users should be able to rely on the billed measurement results;
  • the quantity of goods declared on the packaging is actually contained therein;
  • the standards used in the test are traceable to the SI units;
  • high-quality measurement data is available and permanently available.

Reverification is the most prescribed method for checking the measuring stability of measuring instruments. If a measuring instrument meets the legal requirements, the relevant enforcement authority confirms this with a red verification mark.

Alternatively, the responsible user can keep a control register in which the status of the verification can be viewed.

Another method for maintaining measurement stability is the statistical test method. The responsible body shall check whether the condition and metrological properties of a sufficiently large lot of measuring instruments of the same design comply with the regulations. These tested measuring instruments have no (red) verification marks.

Review with users of measuring instruments

The review of measuring instruments is an inspection of the user of the measuring instrument. In doing so, the enforcement bodies check at irregular intervals,

  • whether the measuring instrument is suitable for the intended use and whether it is being used lawfully;
  • whether the measuring instrument has the prescribed conformity marks and, if applicable, verification marks;
  • whether the prescribed procedures for maintaining measurement stability have been carried out in a timely manner.