What is Calibration?
Calibration is when you check a piece of measuring equipment against a known standard of much greater accuracy.
For example, micrometers are checked against a master slip gauge set, multimeters are checked against an electronic calibrator that outputs known voltages/currents etc, and torque wrenches are checked against a master torque transducer.
How long before I get my item back?
All items that can be calibrated in-house by Thorcal will be calibrated and ready for dispatch within 3 working days of us receiving the item.
Items needing repair or calibration by one of our trusted partners may take longer to assess, or for parts to arrive, but we'll advise of lead time once we've inspected your unit.
What is Traceable Calibration?
Traceable to National Standards means that you can trace the master gauges used to calibrate your equipment back to the standards of measurement at your country's national measurement laboratory, or the SI units of measurement.
In practice, this means that the master gauges Thorcal use have been calibrated by a UKAS laboratory accredited to ISO17025, and the certificate numbers of these traceable instruments are detailed on the certificates we produce.
Amongst other requirements, UKAS laboratories reference their lab standards with each other and the National Physical Laboratory at Teddington, to ensure traceability back to the National Standards themselves (things such as THE 1KG weight) or the SI units of measurement.
Do I need UKAS calibration?
You should ask your auditor what standard of calibration you need for your equipment.
Traceable calibration is satisfactory for the vast majority of customers needs.
If you are an ISO 9001 registered company, part of the standard states that any measuring equipment you use should be calibrated regularly to ensure integrity, but doesn't state that you need UKAS accredited calibration. This standard is reserved for only certain situations and you should check with your auditor if you are unsure.
What instruments can be calibrated on site?
Thorcal can calibrate the vast majority of instruments on site with sufficient uncertainty. There are however some items that need laboratory conditions, or the equipment required for calibration isn't portable enough to bring to site. Contact us to see if we can test your equipment on site.
Is Calibration the same as Repair?
My meter is faulty, does it need calibrating? There’s often a misunderstanding that calibration and repair are the same thing. While calibration can involve adjustment of your instrument, it’s not the same as a repair.
But my meter has been calibrated and it has failed. What now?
Your meter could have failed for several reasons, but the most common are that the unit is either out of tolerance (OOT) or faulty. If your instrument is adjustable, your calibration provider should be able to adjust the instrument back into specification. If the unit is clearly faulty (with functional failures / wildly sporadic readings etc) the unit will need to be assessed for repair.
While technically, calibration is only the checking of the instrument against the master gauge, many calibration providers include adjustment in with the service, which is probably where some of the confusion around calibration/repair has come from.
Adjustable instruments have built in mechanisms to change their parameters. Most torque wrenches can be adjusted, as can many pressure gauges, and some electronic instruments with internal potentiometers.
Some instruments can’t be adjusted, either because there is no mechanism for adjustment, or because they have reached to limits of their adjustable range. If this is the case, then your unit is classed as faulty and will either need more extensive repair, or may be beyond economical repair and a replacement is needed.
Your calibration provider will often have an in-house repair team who can assess the instrument for repair and provide a quote.
What happens if my instrument fails calibration?
We'll send you a detailed fault report advising the reasons your item failed, and suggesting next steps.
If your item is adjustable, we'll adjust it and provide you with a certificate that details the before and after results.
If the item is faulty, we'll inspect the item and provide you with a quote for repair.
In the event we can't repair it in house, we'll gain a quote from one of our trusted partners or the manufacturer, and get your permission to send it away. We'll manage this process for you.
If your item is unrepairable, or you don't want to go ahead with the quote, we'll mark the item as rejected and return it to you with the fault report. Our sales department will quote you for a new item.
How often should I get my equipment calibrated?
Short answer: Ask your auditor.
While the bottom line is usually “ask your auditor”, it can help to know what to consider when picking a calibration interval. Generally speaking, the amount of time between calibrating an instrument should be decided in a conversation with your auditor. If you are an electrician, this might be your NICEIC contact, or if your are in wider industry this is probably your ISO9001 auditor. Things to consider when picking calibration frequency are how often the instrument is used, how likely it is to deviate from correct readings and how critical to the process the instrument is.
How often is the instrument used?
Do you use it every day? Several times a day? Or does it sit in a cupboard until it is used annually. How often you use the gauge should be a major factor in deciding how often to calibrate. The more often an instrument is used, the more likely it is to deviate through use, develop faults, wear etc, and so should be calibrated more often.
How likely is the instrument to deviate?
All gauges will deteriorate over time, but some are more likely to deviate than others. Testers like modern Multimeters and Multifunction testers are unlikely to deviate with time, and are much more likely to develop faults than simply stray out of tolerance. Similarly slip gauge sets and high tolerance hand weights, unless damaged, are unlikely to deviate naturally over time. The opposite is something like a Torque Wrench where, if left wound, the spring can stretch over time, or personal gas monitors, where the cells’ lifespan can make long calibration intervals dangerous.
How critical is the instrument to the process? or to safety?
Some instruments will be more important than others in your process. For example, is your torque wrench used to tighten wheel nuts? What would happen if there was a failure? These are important questions to ask when deciding on a calibration frequency. The more critical the instrument is, the more often it should be calibrated.
In summary, an item that is used every day, can degrade over time, and is used on a safety critical process should be checked much more regularly than an item that is used infrequently, is unlikely to deviate, and is used on a non-critical process. Just to emphasise, the calibration frequency you decide should always be agreed in a conversation with your auditor or governing body.