The BIPM offers a calibration service for 1 kg national prototypes in Pt-Ir. This service is available free of charge to Member States. The Physical Metrology Department maintains a number of prototypes and other standards in Pt-Ir. A subset of these are used as working standards to calibrate national prototypes upon request. The remainder are used for quality control. The standard uncertainty currently assigned to the calibration of a national prototype depends on the time since the last use of the IPK. The last use of the IPK was in 2014 and the combined standard uncertainty of the calibration of national prototypes is currently 0.0045 mg.
The BIPM also fabricates Pt-Ir prototypes for Member States upon request.
- Request the calibration of a national prototype