Standard vs Accredited Calibration and Considerations in Choosing a Calibration Provider
When it comes to equipment calibration services, you have options, which can make decisions a little complex. With that in mind, let’s break down the two most common options to get a better understanding of what they are and when they are necessary.
Properly calibrated instruments help increase confidence for those using the equipment. As a calibration provider, we deliver information about the instrument’s performance and condition and provide a certificate as evidence of service for each piece of equipment calibrated. The calibration certificate is the official document of record for instrument calibration and provides traceability to the National Institute of Standards and Technology (NIST). The accuracy and completeness of the calibration certificate itself is reflective of the validity and credibility of the calibrating organization.
The two most common calibration levels are standard and accredited calibration.
First a quick definition of both:
Standard Calibration (ANSI/NCSL Z540.1)
This service provides a calibration certificate with a calibration date and calibration due date. A traceability statement is provided. Measurement parameters not meeting the test specifications (out of tolerance) are identified and reported on the certificate.
17025 Accredited Calibration
Instrumentation is calibrated in accordance with ISO/IEC 17025 within our approved scope of accreditation. Accredited calibrations provide a certificate of calibration with the accrediting body's logo on the document. The calibration date is on the certificate and the calibration due date is only placed on the document when specified by the customer or contractually agreed. A traceability statement is provided. Measurement data and uncertainty for each parameter tested during the calibration is provided.
Considerations in Choosing a Calibration Provider
It's important to note that non-accredited calibration laboratories are not required to have any type of formal quality system nor provide measurement data to their customers. They may not follow regulations that govern the technical aspects of the calibration laboratory to ensure that the proper training and methods are applied to the calibration process.
Meanwhile, accredited calibration laboratories are governed by the international standard ISO/IEC 17025 and are regularly audited by various recognized accreditation bodies to test the laboratory’s technical competence and that they follow a proven quality management system. They are guided by quality and integrity in all aspects of their job performance.
Quality may not necessarily matter depending on the role of the equipment being calibrated – performing functions not considered critical or have a wide tolerance variance. However, if an organization is creating parts considered essential or with very little tolerance, an accredited calibration provider might be your best option. It’s about risk. All measurements (ruler, electrometer, thermometer, etc.) have some degree of uncertainty in the measurement. What variability in measurement is acceptable? If a measurement tolerance is .01 and the level of uncertainty in measurement is .001, the risk is relatively low. If the tolerance and uncertainty were reversed, the calibration would be inadequate and would provide a high level of risk to the user. The level of uncertainty allows an informed decision to be made about the acceptability of measurements.
While accurate calibration is always important, the degree of tolerance can guide your decision to choose accredited versus non-accredited. Generally speaking, accredited calibration is a must when accuracy is paramount. Industries such as aerospace, automotive, healthcare, and aviation require extreme accuracy. Improper calibration of a component can present an enormous risk in aircraft damage and in the loss of lives. One, real-life example is Lion Air Flight 610 that crashed shortly after takeoff in October of 2018 in Indonesia. The suspected improper calibration of one of the Angle of Attack (AOA) sensors is believed to have caused erroneous data to be sent to the Maneuvering Characteristics Augmentation System (MCAS) system. This caused the MCAS to activate multiple alerts and repeatedly produced flight control issues with the aircraft that the pilots could not properly manage. The flight crashed into the Java Sea killing 189 passengers and crew.
Non-accredited calibration laboratories are not required to have any type of formal quality system nor provide measurement data to their customers. They may not follow regulations that govern the technical aspects of the calibration laboratory to ensure that the proper training and methods are applied to the calibration process.
Overall, calibration is crucial because out-of-tolerance (OOT) instruments may give false information leading to unreliable products, customer dissatisfaction and increased warranty costs. In addition, OOT conditions may cause good products to fail tests, which ultimately results in unnecessary rework costs and production delays. Minimize risk by choosing a calibration service provider who can support your instruments and meet your regulatory requirements.