National Metrology Institute of Japan : NMIJ

Legal Metrology

§ Type Approval

Specified measuring instruments are required to pass the appropriate tests to verify that their structures satisfy the technical standards specified by the Measurement Law before these instruments are put into commercial production. Such testing process conducted by the Japanese government (or agencies certified by the government to administrate the tests) is called type approval. The tests include electric noise tests and durability tests as well as various performance tests.

Various kinds of equipments are necessary to test the performance of measuring instruments for type approval. Typical testing apparatuses include EMC testers and Nonautomatic weighing instruments temperature testers.

§ Inspection of Verification Standards

Verification standards are measuring instruments that are used, from the viewpoint of implementation of precise measurement and maintenance of accurate measuring instruments, as standards for inspecting specified measuring instruments at the time of verification, periodic inspections and other relevant opportunities. The inspection of verification standards is a system to check if they satisfy the minimum required performance by verifying the structures and instrumental errors of the standards. This service is carried out jointly by the Tsukuba Center and the Kansai Center's Ogimachi Site. They also carry out the inspection of verification standards for liquid column pressure meters and density hydrometers.