2, mandatory calibration of measuring instruments must be regularly scheduled by the statutory or authorized measurement and calibration institutions. 3, non-compulsory calibration of measuring instruments, can be used by the unit according to law on their own regular calibration. The unit can not be certified by the authority to carry out the work of the measurement of the value of the transfer of the measurement and verification institutions for verification. Measurement and verification work should be carried out in accordance with the principle of economic rationalization and proximity.
4, the unit's own verification and calibration, must be certified by the measurement inspector to carry out the personnel.