Measuring instruments, which are subject to registration and shall be used in areas of state supervision in Russia, have to be calibrated initially before commissioning. Initial calibration can also be called a Primary Verification. During operations the measuring equipment shall be calibrated regularly. The calibration, which ensures the accuracy of measured variable of the instruments is defined in the Federal Law of the Russian Federation no. 102 “On ensuring the uniformity of measurements":
Primary Verification of measurement equipment is a set of operations performed in order to confirm the conformity of measuring metrological requirements
The metrogical certificate is a necessary prerequisite for the initial calibration of measuring equipment.
The calibration is carried out by an accredited certification body in Russia. Each device must be calibrated separately. After the successful completion of the initial calibration a Primary Verification Certificates is issued and a calibration mark can be attached on the measurement equipment. The results of the initial calibration are registered as well in the instruction manual or in the technical passport .
The results of the initial calibration are registered in the federal directory.
Such measuring devices that do not underlie any state supervision can be calibrated voluntarily.
Along with a primary verification there is a periodic verification. It is a verification of measuring instruments which are used or stored, and is carried out at set time intervals between calibrations.