What Is Calibration?
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Calibration focuses on the comparison of a measuring instrument, the Unit Under Calibration (UUC) to a Standard of known accuracy. The standard would ideally be more accurate than the UUC and have its own calibration certificate which can be traced back through an unbroken chain of calibrated standards to an appropriate standard held by a National Laboratory. In the UK, this would be the National Physical Laboratory (NPL).
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UKAS Calibration Certificates
A UKAS calibration is a calibration undertaken by a laboratory, who have been independently audited and subsequently accredited by UKAS to ISO/IEC 17025 to conduct the calibration.
UKAS calibration certificates should be instantly recognisable by the UKAS calibration accreditation symbol featuring the Royal Crown. This is printed in the top right-hand corner of the front page.
The certificate should detail the measurement results of the calibration, the associated measurement uncertainty, before and after any adjustments if applicable and a statement of conformance with an identified metrological specification or clauses thereof where available.
It is not possible to obtain a UKAS calibration certificate for every conceivable piece of measuring equipment. For some types of instruments, no laboratory has been accredited. It may be that an accredited laboratory has additional capabilities, which have not been accredited. An 'In-House' or ‘Class 1’ calibration certificate would usually be offered in these circumstances. Whilst not bearing the UKAS accreditation symbol featuring the Royal Crown, this certificate should, at the very least, detail the measured results of the calibration and the associated measurement uncertainty.
Our current UKAS Schedule of Accreditation can be downloaded via the UKAS website.
You can find us by selecting ‘search accredited organisations’ from the home screen and search for our UKAS customer number ‘0125’, our company name, or by clicking here.
Unfortunately, many ‘Certificates of Calibration’ supplied with new instruments do not meet any of the above criteria. This makes them no more than 'Certificates of Conformity' rather than true calibration certificates. These would not normally be acceptable to an auditor.
UKAS Accreditation, ISO/IEC17025
Calibration laboratories are accredited by UKAS to the recognised International Standard ISO/IEC 17025 for the competence of testing and calibration laboratories.
Our management systems, personnel and our technical capabilities are thoroughly examined and assessed each year by a team of UKAS assessors, each of them specialists in their field. It is an expensive and time-consuming process, but our ongoing commitment to accreditation and the fulfilment of the requirements of ISO/IEC 17025 means that you can be assured we have the competence, impartiality and performance capability necessary to consistently deliver technically valid calibration results every time.
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We hope you have found this information useful and invite you to contact us if you require any further information or assistance with your calibration requirements.
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Who are UKAS?
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The United Kingdom Accreditation Service (UKAS) is the sole National Accreditation Body for the United Kingdom. UKAS is recognised by government, to assess against nationally and internationally agreed standards, organisations that provide conformity assessment services such as certification, testing, inspection, calibration and verification.
Accreditation for calibration laboratories by UKAS to ISO/IEC 17025 demonstrates the competence, impartiality and performance capability of these evaluators. In short, UKAS ‘checks the checkers’.
We hope you have found this document useful and invite you to contact us if you require any further information or assistance with your calibration requirements.