Laboratory Accreditation and Accreditation Body Symbols on Calibration Certificates

What does it mean for a calibration lab to be accredited to ISO 17025?

ISO/IEC 17025:2017, “General requirements for the competence of testing and calibration laboratories” is the primary quality standard that most calibration laboratories strive to meet. A nice overview is available on Wikipedia2: “The ISO/IEC 17025 standard itself comprises five elements that are Scope, Normative References, Terms and Definitions, Management Requirements and Technical Requirements. The two main sections in ISO/IEC 17025 are Management Requirements and Technical Requirements. Management requirements are primarily related to the operation and effectiveness of the quality management system within the laboratory. Technical requirements include factors which determine the correctness and reliability of the tests and calibrations performed in the laboratory.”

Accreditation refers to an audit/assessment by a third party, generally known as an Accreditation Body (AB), attesting to technical competence within a laboratory specific to a Scope-of-Accreditation (in addition to adherence and operation under a documented quality system).

How important is the Scope-of-Accreditation when I am considering using that calibration laboratory?

In short, very important. The accreditation body assessors review technical competence for only those measurement parameters in the Scope-of-Accreditation. If a lab Scope includes only DC volts, ohms, and DC current, then that is all the audit covers. Unfortunately, some labs offer calibration services outside of their Scope. When they do this, it means that an independent assessor has not verified the technician competence, the best measurement capability, and the associated measurement uncertainties for any parameters not covered in the audit. When you send your instrument to an Americas Keysight Technologies, Inc. service center, you can be certain that ALL measurements performed on your instrument have been covered in the Scope of that lab. The Keysight Roseville, CA service center Scope-of-Accreditation covers > 55 measurement parameters covering measurements from DC to above 50 GHz, as well as optical. A list of all Keysight service centers Scopes-of-Accreditation is available at: www.keysight.com/find/accreditation.

Can a calibration lab also be accredited to ANSI Z540.3?

Yes, absolutely. Most Accreditation Bodies audit first to ISO/IEC 17025:2017, then as requested to the incremental requirements of ANSI Z540-1-1994, or ANSI/NCSLI Z540.3-2006. Keysight Americas service centers are accredited to ISO/IEC 17025:2017, ANSI Z540-1-1994, and ANSI/NCSLI Z540.3-2006.

For more information on ANSI Z540.3, please visit: www.keysight.com/find/Z540.3.

Is there a special significance if an AB symbol appears on my calibration certificate?

Accreditation bodies provide specific guidance on requirements to place their accreditation symbol on the calibration certificate for a particular instrument. While these may vary a little by country, or AB, the critical requirements do not. These are:

All measurement results must be included in the lab scope-of-accreditation, or if not, must be clearly denoted as non-accredited measurements in the report.

Measurement uncertainty per the ISO GUM3 must be included in the measurement report along with all measurements. Please see paragraph 6.1 of ILAC-P14:01/2013, “ILAC Policy for Uncertainty in Calibration”.

Note: The Jan 2013 version of ILAC-P14 does allow, by exception, the calibration lab to omit the measured quantity value and measurement uncertainty, by specific contract agreement if the instrument is “not intended to be used in support of the further dissemination of metrological traceability (i.e. to calibrate another device)”. However, the lab is still required to meet” ISO/IEC 17025 clause 5.10.4.2 and determine the uncertainty and take that uncertainty into account when issuing statement of compliance: and the laboratory shall retain documentary evidence of the measured quantity value and the uncertainty of measurement, as specified in ISO/IEC 17025 clauses 5.10.4.2 and 4.13, and shall provide such evidence upon request.”

Keysight chooses to always show the work performed so that there is no question of what has been measured, the corresponding measurement uncertainty, or how measurement uncertainty is taken into account in the assessment of Pass or Fail.