Thread Content
Calibration and verification are two fundamental terms in metrology; many people, due to a lack of clear understanding, tend to confuse or equate the two. We will distinguish them for you from the following ten aspects. 01 Different objects: The objects used for calibration are measuring instruments that fall outside the scope of mandatory verification, for which there are no measurement verification regulations, or for which existing regulations are not applicable, as well as those for which no means of verification exist. The objects of verification are the measuring instruments subject to mandatory verification as clearly stipulated in our country’s Metrology Law. 02 Basis: The basis for calibration is the calibration specification or method; these can be **uniformly prescribed or determined independently. The calibration specifications can define requirements regarding calibration procedures, methods, calibration intervals, calibration records, and identification. The basis for calibration is the currently valid metrological calibration regulations, which have been approved and published in accordance with legal procedures. 03 Different purposes: The purpose of calibration is to determine the relationship with the corresponding standard value. The purpose of verification is to conduct a mandatory comprehensive assessment of the metrological properties of measuring instruments; it is a top-down process for the transfer of measurement values. 04 Different in nature: Calibration is not mandatory; it involves testing in accordance with the steps specified in the calibration guidelines, and not all items necessarily need to be tested. Verification is mandatory; it is carried out in accordance with the **metrological system table, through comprehensive testing following the procedures specified in the metrological verification regulations, and carries legal validity. 05 Different subjects: The subject for calibration is a person qualified to perform calibration. The personnel responsible for calibration must have passed the relevant assessments and hold a certification as a calibrator issued by the competent metrological authorities. 06 Different methods: The proper method can be self-calibration or external calibration. Where conditions permit, calibrating measuring instruments using self-calibration methods can save a significant amount of money. Calibration must be carried out at a qualified metrological administrative department or an institution authorized by law. The calibration cycle for cycle 07 varies; it is determined based on the frequency of use or the level of risk associated with the measuring instrument. Calibration can be carried out on a regular basis, irregularly, or even before use. The calibration cycle must be determined in accordance with the provisions of the metrological calibration regulations; it cannot be set arbitrarily. 08 The content is different; calibration is intended solely to assess the indication error of measuring instruments in order to ensure the accuracy of the measured values. The content of verification is a comprehensive evaluation of measuring instruments. In addition to all the elements involved in calibration, relevant tests also need to be carried out. Verification can replace calibration, while calibration cannot replace verification. 09 Conclusion: The conclusion of calibration does not require a determination of pass or fail. Only the range, error, or measurement uncertainty is given. The calibration results can be recorded in a calibration certificate or calibration report, and can also be expressed in the form of calibration factors or calibration curves. The verification must, based on the range of permissible value errors specified in the verification regulations, render a determination as to whether the measuring instrument is qualified or unqualified. If the inspection results are satisfactory, an inspection certificate is issued; if not, a notice of inspection results is issued. 10 Different risk burdens: The risk associated with calibration is borne by the entity that uses the measuring instrument. The risk of the inspection is borne by the department conducting the inspection. Calibration and verification are fundamentally different, yet closely related. Both calibration and verification are effective and reasonable methods and means for traceability of measurement values, with the aim of achieving the traceability of such values.