The quality of a production process ultimately depends on the quality of the measurements on which it is based. An instrument that measures inaccurately — even by a few tenths — can compromise a product's conformity, generate scrap, or reveal nonconformities during an audit. The calibration of measuring instruments is the practice that ensures the reliability of these measurements over time.
Calibration is a documented technical operation that compares the values measured by an instrument with the values provided by a reference standard of known accuracy, traceable to national or international standards.
The result of a calibration is a calibration certificate: a document that reports the deviations found between the value measured by the instrument and that of the reference standard, the environmental conditions during the test and the associated measurement uncertainty.
Calibration does not necessarily include an adjustment: the instrument is measured as it is, and the operator then decides whether the detected error is acceptable for the intended use.
The two terms are often used interchangeably, but in practice they indicate distinct operations.
Calibration consists of the documented comparison between the instrument and the reference standard. It provides information on the metrological status of the instrument but does not necessarily involve corrective action.
Adjustment (in the Italian technical sense often referred to as calibrazione, also called regulation or correction) is the operation that follows calibration when it is decided to correct the instrument's response by acting on internal parameters or correction coefficients.
In practice: calibration first, adjustment (if necessary) afterwards.
Calibration ensures that measurements produce reliable and comparable results over time and between different laboratories. The main reasons to keep it up to date are:
In Italy, calibration with recognized metrological value can be performed by:
ACCREDIA is the sole Italian accreditation body, recognized by the European Commission. A certificate issued by an ACCREDIA-accredited laboratory guarantees that the calibration was carried out according to validated procedures, with reference standards that are themselves traceable to the national and international metrological chain.
When requesting an accredited calibration certificate, the document will include the ACCREDIA logo and the laboratory's accreditation number — elements that attest to its validity for regulatory and contractual purposes.
There is no universal calibration interval: the frequency depends on several factors specific to the instrument and its context of use.
A common starting point for most laboratory and production instruments is annual calibration, but many critical systems — load cells, universal testing machines, extensometers — are calibrated semiannually or after each maintenance intervention.
In addition to scheduled calibration, there are situations that require an extraordinary calibration regardless of the planned interval:
An uncalibrated instrument or one with an expired calibration does not provide guarantees about the accuracy of its measurements. Practical consequences may include:
Accredited calibration is performed by an ACCREDIA-certified laboratory and has recognized regulatory value. In-house calibration may be sufficient for process control, but it is not accepted for product certification or system quality purposes.
Yes. Calibration without documentation has no metrological value. The certificate must report the measured values, the uncertainty, the operating conditions and the traceability of the reference standard used.
Calibration certifies the metrological characteristics of the instrument at a given moment. If the detected error falls within the tolerances required for the application, the instrument is suitable for use. If it exceeds them, it must be adjusted or replaced.
It depends on the risk associated with the application. For non-critical uses, a slightly out-of-calibration instrument may be acceptable with appropriate warnings. For regulatory or safety applications, no.
Times vary depending on the laboratory and the type of instrument. Generally from a few days to a few weeks for standard instruments. For complex instruments or those with special geometries, dedicated procedures may be required.
Galdabini offers an accredited calibration service for universal testing machines, load cells, extensometers and measuring instruments for mechanics. The certificates issued comply with ISO 9001 and ISO/IEC 17025 requirements and include the ACCREDIA logo.
Do you need to calibrate your instruments or do you have an upcoming deadline? Contact our team to receive a quote or to schedule the intervention.
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