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What is the Difference Between ISO 17025 and NIST Calibration?

Calibration | iso 17025

When searching for the right pressure gauge for your application, you need to consider a number of factors. What range gauge do you need? What type of pressure are you measuring? Does your application require specific validation standards?

You might require a pressure gauge that’s certified to ISO 17025 or has its calibration traceable through NIST. What’s the difference between the two certifications?

This can cause some confusion, and it’s a question that our customer service team receives regularly. This article will attempt to explain what each calibration means and what is involved in receiving the certifications.

What is ISO 17025 Accredited Calibration?

ISO 17025 certification is a calibration service that has been approved by an independent accreditation body. During the accreditation process, the laboratory needs to prove the traceability of its measurements to a national or international standard. It’s an expensive service, so you should be sure that this calibration is truly required for your application.

An ISO/IEC 17025 accredited calibration addresses the calibration laboratory and its ability to produce data that is accurate and precise to an internationally recognized standard.

According to the ISO 17025, national metrology institutes, such as the NIST, can be internationally recognized for acceptable measurement traceability, but it is up to the end user to decide what to accept for the traceability, NIST or another national or international agency.

One way to achieve metrological traceability is to use a third-party organization such as ANSI-ASQ ANAB. These organizations perform an audit on the laboratory and its processes to determine if it can successfully perform calibrations and issue accredited calibration results.

The audit is performed regularly to ensure continued ISO/IEC 17025 standard compliance.

ISO/IEC 17025 accredited calibration can be considered a cut above NIST because it not only includes measurement traceability but also measurement uncertainties of the calibration results.

With ISO/IEC 17025 certification, laboratories create confidence in their work by demonstrating that they are competent and get valid results.

This certification looks at several different factors:

  • Effectiveness of a lab’s quality management system
  • Staff competence
  • Environmental controls
  • Testing methods
  • Equipment/measurement traceability
  • Testing and calibration result reports

Achieving this certification can help with international trade, as well. Labs that are accredited can have their test reports accepted in other countries without further testing. This wider acceptance of results between countries helps build stronger relationships between laboratories around the world.

What is NIST Traceable Calibration?

The National Institute of Standards and Technology (NIST) is a non-regulatory federal agency under the Department of Commerce. NIST certification means a product has been tested against NIST standard reference materials (SRM) and meets the exacting requirements for that product.

NIST traceable calibration means that a manufacturer or laboratory can certify that the standards used to calibrate a device can be traced to NIST.

This type of calibration does not look at the level of competence of the staff and laboratory that performs the calibrations like ISO 17025 does. It focuses on the standard used in the calibration and assures that it’s traceable to NIST.

In addition to pressure gauges, the NIST also certifies products such as clocks, thermometers and timers.

Do I Need NIST or ISO 17025 Calibration?

With both calibration standards available, how do you know which one is the best option for your process? Your business’s quality manual or the quality department can help with this decision.

You can also decide based on how the equipment that requires regular calibration will be used.

If your equipment is being used in a critical application with a liability risk if something went wrong, ISO 17025 calibration would be a good option. Such applications can include processing laboratories, medical equipment or power plants.

If your device is used more for low-risk reference purposes where the measurement doesn’t require the highest accuracy, an NIST traceable calibration is acceptable. These applications can include process gauges, pressure switches and pressure dial gauges used for air compressors.

We don’t like to pressure you, but we have more information.

You should now understand the difference between ISO 17025 and NIST certifications. There are several factors to consider when deciding if you want to calibrate your equipment to a certain standard, including cost and the accuracy requirements of your application.

Be sure that your application truly requires strict certifications before you go through the calibration process to save your business time and money.

If you want to learn more about pressure gauges, you can visit our resource center.

You can also check out some of our other blog posts about gauges:

Feel free to contact us today to talk to one of our industry experts and get all your pressure gauge questions answered.

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About Todd Zeigher, Quality Assurance Manager

Todd started with Ashcroft in 2021 but has over 30 years of experience in manufacturing and product development of industrial/commercial, consumer, automotive and medical products. One of Todd’s core beliefs is to put your best foot forward and get it right the first time; your customers will thank you. Todd holds a BS in Industrial Engineering, an MS in Manufacturing Engineering and an MBA in Marketing. In his spare time, Todd enjoys skiing, home improvements and furniture restoration projects, and he is a passionate mountain biker.