A calibration system is a set of operations that establish, under specified conditions, the relationship between a measuring device and a traceable standard of known reference value and uncertainty. Calibration may also include steps to detect, correlate, report, or eliminate by adjustment any discrepancy in accuracy of the measuring device being compared.
The calibration system determines measurement traceability to the measurement systems through the use of calibration methods and standards.
Traceability is the chain of calibration events originating with the calibration standards of appropriate metrological capability or measurement uncertainty.
Each calibration event includes all of the elements necessary including standards, measurement and test equipment being verified, calibration methods and procedures, records, and qualified personnel.
An organization may have an internal calibration laboratory or organization which controls and maintains the elements of the calibration events. These internal laboratories will maintain a laboratory scope which lists the specific calibrations they are capable of performing as well as the equipment and methods/procedures used to perform the calibrations.
The calibration system is part of an organization’s quality management system and therefore should be included in any internal audit requirements.
Measurement Assurance Programs (MAPs) can be used to verify the acceptability of the measurement processes used throughout the calibration system. Generally MAPs will include verification of a measurement system’s results through a secondary independent measurement of the same feature or parameter. Independent measurements imply that the traceability of the secondary measurement process is derived from a separate chain of calibration events from those used for the initial measurement. MAPs may also include the use of statistical process control (SPC) to track the long-term stability of a measurement process.
Note: ANSI/NCSL Z540.3 and ISO 10012 each provide models for many of the elements of a calibration system.
When the calibration event is performed by an external, commercial, or independent calibration service supplier, the service supplier’s calibration system can (or may) be verified through accreditation to ISO/IEC 17025.
When a qualified laboratory is not available for a given piece of equipment,calibration services may be performed by the equipment manufacturer.
source of Calibration System: Analysis of measurement systems
