Certificates of Calibration Explained

Dwyer Instruments, Inc. offers a variety of calibration services for new or previously purchased products. In 2019, the Dwyer Instruments, Inc. – Engineering Laboratory, located in Michigan City, IN, gained accreditation to ISO/IEC 17025:2017 through the ANSI National Accreditation Board. The Dwyer lab now offers two different types of calibration certificates for our products: a certificate of NIST calibration and an ISO/IEC 17025:2017 accredited certificate of calibration. Now that accredited calibration services are available for select Dwyer products, it is important to know the differences between these two different calibration certificates. Knowing these differences will allow you to understand which calibration certificate will best suit your needs.

Certificate of NIST Calibration

Certificate of NIST Calibration Sample

The Certificate of NIST Calibration is created in our testing lab and is available to customers at an additional charge. This certificate indicates that a product was calibrated in our laboratories against measurement and test equipment (M&TE) that are traceable to the International System of Units (SI) through NIST. These Certificates of NIST Calibration are unique to each product and contain product calibration data, M&TE information, specific product information (e.g. unique serial number, manufactured date code, and model number), as well as customer information. For some individuals, this Certificate of NIST Calibration satisfies their quality system requirements for demonstrating historical evidence of calibration records for their equipment. A Certificate of NIST Calibration should be purchased when the device is to be used in non-critical, low-risk measurement applications, as the certificate can give a good idea of instrument performance without over-complicating the records.

In summary, the Certificate of NIST Calibration includes:

  • Unique product calibration data
  • Measurement and test equipment information
  • Specific product information
  • Customer information

ISO/IEC 17025 Accredited Certificate of Calibration

Accredited Certificate of Calibration Sample

While there is a lot of helpful information on the Certificate of NIST Calibration, some customers require more thorough documentation. Available for select products, our ISO/IEC 17025 Accredited Certificate of Calibration is created by our ANAB Accredited Standards Laboratory. An ISO/IEC 17025 Accredited Certificate of Calibration takes the information included in the Certificate of NIST Calibration and elaborates on it. This certificate guarantees that the calibration work performed is in agreement with the internationally recognized standard ISO/IEC 17025:2017. The measurement and test equipment used in the accredited calibration process are traceable to appropriate globally-recognized National Metrology Institutes (such as NIST in the United States or PTB in Germany) and are calibrated at routine intervals. Similar to the Certificate of NIST Calibration, this certificate includes information about the M&TE used and the product calibrated, but it also takes a deep dive into the policies and procedures used during the calibration work. 

This deep dive is important because compliance to ISO/IEC 17025 requires a high level of competence among the staff of the laboratory and ensures a high quality calibration. Detailed information is provided in regards to the data obtained for the unit under test (UUT). For each measurement performed, there is an associated measurement uncertainty. This uncertainty is shown graphically on each certificate and provides insight as to the uncertainty contribution of the M&TE used in the calibration and how well the UUT performs. An ISO/IEC 17025 certificate will impress audit parties, as it demonstrates true traceability to NIST (or other NMI’s where appropriate) for the M&TE and the UUT. Furthermore, the international body logos on these certificates identify the work as having been performed by an internationally recognized laboratory.

The ISO/IEC 17025 Accredited Certificate of Calibration includes:

  • All information included in Certificate of NIST Calibration
  • Measurement uncertainties for each data point
  • ISO/IEC 17025 compliant calibration 

While many companies offer some sort of certificate of calibration, not many can offer an accredited calibration certificate. The ISO/IEC 17025 Accredited Certificate of Calibration is a step above a Certificate of NIST Calibration. ISO/IEC 17025 calibration is crucial for equipment that is used in critical applications where some risk is associated with each measurement/process where the instrumentation is used. Purchasing an ISO/IEC 17025 Accredited Certificate of Calibration is the best way to minimize risk in measurement processes, demonstrate true traceability to the SI units, and prove that you are using a calibration provider that truly cares about quality, measurement accuracy, and overall consistency. When considering calibration services for your Dwyer equipment, use a calibration provider you can trust by choosing the Dwyer Instruments, Inc – Engineering Laboratory.