Why is it necessary to perform calibration of measuring instruments ?

SDM-21coor-Measuring instruments play an important role in the manufacturing process, ensuring the product conformity.

Such an important role requires the instrument to be efficient and with an error proportionally adjusted to the product tolerance.

Every measuring instrument is subject to a deterioration of its initial error, both through the use and age. Monitoring that the instrumental error is appropriate for the use for which it is intended. has thus become mandatory.

That is why it is necessary to check the calibration. There is no obligation to perform calibration of measuring instruments, but only a technical reason to guarantee the production and metrological characteristics over time.

What is the difference between Calibration Report and Calibration Certificate?

certificato taratura e rapporto taraturaThe Certificate of Calibration is the document issued by a center accredited by ACCREDIA (Italian authority in Italy for the accreditation of testing and calibration laboratories).

The activities related to the issuance of the Calibration Certificate report directly to the requirements of UNI CEI EN ISO/IEC 17025:2005 (General requirements for the competence of testing and calibration laboratories ).  ACCREDIA is responsible of the calibration laboratory performance, through the approval of the measurement procedures, periodical audits and interlaboratory comparisons.

Through these activities ACCREDIA ensures the compliance of the accredited laboratory to all the requirements of the above standard. The holder of such a Calibration Certificate for a measuring instrument has no additional need to demonstrate to any third parties that the metrological service acquired has been carried out in accordance with the provisions of the standard. Moreover, the certificate also guarantees the traceability of the results to national standards.

Calibration reports are issued according to procedures approved by the laboratory, which guarantees the metrological correctness and the traceability.

The holder of such a Calibration Certificate for a measuring instrument has, if required, the additional need to demonstrate to any third parties that the metrological service acquired has been carried out in accordance with the provisions of UNI CEI EN ISO/IEC 17025:2005 standard. He also might be required to document how the traceability of the calibration results is maintained.

How often should I perform the calibration of an instrument?
grafico-deriva-strumenti-misura

The verification of calibration and metrological confirmation must be repeated whenever you suspect that one or more of the metrological characteristics of the measuring instrument has been altered, i.e. after shocks, repairs and/or adjustments.

Apart these particular circumstances, verification and confirmation should be repeated at certain intervals, mostly depending on the use of the equipment.

The best way to define the calibration intervals is through the analysis of the instrumental drift graph.

What is the difference between accreditation and certification ?

accrediaOften there is confusion about the difference between the terms “accreditation” and “certification”.

“Accreditation” means an entity (Authority) which formally recognizes that an organization (or an individual ) is competent in performing a specific service, as described in the scope of accreditation. For example, ISO/IEC 17025 defines policies and procedures specifically prepared to determine the specific technical competence of a laboratory.

“Certification”, however, means that an independent third party has confirmed in writing that a product, process or service complies with the prescribed requirements. For example, an ISO 9001 certified company declares conformity with the requirements of the standard (not connected to specific technical skills) and is primarily concerned with the general management, processes, and data management.

The difference between the two definitions, apparently similar, is that with the accreditation, the formal recognition of competence is based on proven technical knowledge, and therefore requires the assessment by a technical expert, while certification is primarily concerned with ensuring compliance with a given standard.

What is accreditation?

“Attestation by a national accreditation body that a conformity assessment body meets the criteria set…”

«Certification by a national accreditation body that a conformity assessment body meets the criteria set by harmonized standards and, where appropriate, any additional requirements including those set out in relevant sectoral schemes, to carry out a conformity assessment for a specific activity» REG (EC) No 765/2008

Both national and international customers require increasing guarantees about the quality and safety of goods and services purchased. Manufacturers and suppliers must ensure compliance with legislative requirements to compete in increasingly competitive markets.

Through the certification of its management system, product, service or skills, an audit track on its activities, products, measuring instruments and standards, the supplier can prove that he is operating in accordance with international standards and other specific and relevant requirements.

Only test laboratories, calibration laboratories and certification and inspection bodies accredited are able to provide the market (other companies, public administration, final users) with declarations of conformity reliable, credible and internationally accepted. ACCREDIA perform audits by applying the most rigorous standards and monitors continuously their performance, through international agreements of mutual recognition. In particular, accredited calibration laboratories disseminate the metrological traceability of measurement results, in order to guarantee the quality of products and services, in accordance with local and national legislation (Law 273/91), and internationally.

Through the accreditation both conformity assessment bodies (laboratories or certification/inspection authorities) and their customers can testify that adherence to these guidelines is voluntary.

The accreditation demonstrates the level of quality of work of a body (certification and inspection) or laboratory (testing and calibration), verifying the conformity of its management system and its assets to  internationally recognized and/or mandatory legislative requirements.

ACCREDIA is committed, through the implementation of its control mechanisms, to ensure that all bodies involved (companies, consultants, organizations, inspectors ) respect all principles on which the credibility of compliance certificates is based.

Accreditation is therefore a guarantee of:

  • Impartiality: representation of all interested parties within the body /laboratory.
  • Independence: auditors and committees responsible for issuing the certification ensure that no conflicts of interest exists with the accredited organization
  • Correctness: European standards prohibit the provision of consulting services either directly or through affiliated companies.
  • Jurisdiction: The accreditation demonstrates that the staff involved in calibration activities is technically and professionally qualified.

The accreditation covers all areas of production and services. Any activity can be evaluated, i.e. building, environment, transportation, healthcare, education.

The accreditation service is organized as a complex process, going beyond the technical assessment of the competence of laboratories and organizations, pursuing objectives of general interest.