In this blog our technical team explain the calibration terms that are used and answer some of the frequently asked questions our customers ask.
Calibration terms
Measurement traceability is the unbroken chain of comparisons between a given measurement device and national or international standards. It gives you confidence that all measurements are stable, comparable and correct within their associated measurement uncertainty.
Measurement uncertainty is the doubt that exists about the result of any measurement. Explained another way, it is the range of values within which the true value of a measurement lies. All measurements are subject to uncertainty and a measurement result is complete only when it is accompanied by a statement of the associated uncertainty.
Do I need verification or calibration?
Calibration is the comparison of measurement values delivered by test equipment or a test sample with those of standard equipment or a standard sample of known accuracy. It can be used to determine how accurate a measurement instrument is. Measurement uncertainty necessarily increases along the sequence of calibrations.
Verification is a procedure made to help companies ensure their processes or equipment are working the way they were originally intended to. In this procedure, a company will use some sort of measuring device to see if a piece of equipment is operating correctly. It can also refer to a procedure designed to check an entire process to ensure this process meets its stated operating specifications.
You’ll need calibration if:
- Calibration is specified in any of the procedures or legislation you work under in your organisation
- You need corrective action i.e. if the equipment is NOT working according to specification verification will simply tell you that
- You need technicians to check results versus any NIST standards (verification process does not do that).
Do I need UKAS calibration?
Our technical team can help you with this answer if you are unsure, but here we outline in what situation you would require UKAS calibrations over traceable calibrations:
- Industry specific: UKAS calibrations are performed under the most stringent conditions, therefore industries where safety is critical, such as aerospace, oil and gas, and pharmaceuticals, may lean more towards UKAS calibrations for the added level of trust they provide.
- Operational use: Within certain operational environments an inaccurate reading from metrology equipment could pose a massive risk to safety. On the other hand, for non-critical operations such as production testing and simple reference checks some customers feel a traceable calibration is acceptable.
- Quality manual: It’s not uncommon for quality assessors to instruct businesses to calibrate instruments to UKAS standards. This could be a result of a stipulation from the governing or regulatory body of an industry.
- Customer request: Some end customers may request their suppliers have metrology equipment calibrated to UKAS standards to ensure a consistent result all the way along the supply chain, as well as providing an added level of assurance that all the equipment used in production was accurate.
What is traceable calibration?
Traceable calibration refers simply to calibration which is carried out by accurate equipment and produces documentation that shows a chain of values to prove its authenticity. However, traceable calibration does not inherently work against a pre-agreed or widely recognised standard. Items of equipment undergoing traceable calibration are measured purely against the tool calibrating them; the tool itself is not held to any particular standard.
What are the standards governing calibration?
Three key industry standards govern the way calibration is performed around the world today:
- ISO/IEC/EN 17025 (compliant): the most rigorous globally-accepted standard. Prescribes “General Requirements for the Competence of Calibration and Testing Laboratories”. The service organization providing this calibration meets the requirements of ISO17025.
- ISO/IEC/EN 17025 (accredited): the most rigorous globally-accepted standard. Prescribes “General Requirements for the Competence of Calibration and Testing Laboratories”. This is verified by an independent accrediting body operating under ISO17011.
- ANSI/NCSL Z540-1-1994 (R2002): known as “Z540”. A U.S. standard that sets compliance guidelines for “Calibration Laboratories and Measuring and Test Equipment”.
What calibration services does CoMech offer?
Here at CoMech we have a range of laboratories that provide calibrations on multiple assets from a range of industries. Our UKAS scope details what we complete and each page on our website (click here Calibration Services – CoMech Metrology) shows what we offer.
However CoMech provide a full offering of calibration enabling you to reduce your number of vendors and rely on one partner to handle everything that needs calibrating within your organisation. We have service level agreements in place with subcontractors enabling us to manage your calibration to a high standard when it is an asset that can’t be completed within the CoMech laboratories.
What do you come onsite to calibrate?
CoMech’s onsite calibration engineers can complete traceable or UKAS calibrations on a range of assets at your site. Typically, there will be equipment that requires calibration that can’t easily be transported such as temperature gauges in food and drink manufacturing sites or within the aviation sector items like ESD mats and M1 bonding meters that need to stay on site are calibrated. There are always things like industrial washing machines, balances, ovens and pressure gauges that need to be completed onsite due to immediate usage, or sheer size of the items.
How do I know when my equipment needs calibrating?
Calibration schedules depend on the usage of your tooling or equipment, manufacturers specifications or legislation requirements. Most customers have a good understanding of when items need calibrating. What is often missing is an easy-to-use system to alert the relevant people within an organisation when calibrations are due.
CoMech have developed an asset management system that provides full traceability for your calibration; you can easily find your certificates that detail when the calibration was completed with the results. The real advantage is that TrackRecordPro will alert the relevant people within the business for when assets are due in for calibration.
If you have any questions for our technical team please don’t hesitate in sending them to sales@comech.co.uk and we’ll get them answered!
