Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revisionPrevious revision
Next revision		Previous revision
Last revisionBoth sides next revision
articles:nist_traceability [2020/01/23 10:16] – [Conclusion] rrandallarticles:nist_traceability [2021/11/10 06:49] – [What are SI Units?] rrandall
Line 6: Line 6:
  
 <WRAP center round box 80%> <WRAP center round box 80%>
-**[[https://www.nist.gov/document/gmp-13-ensuring-traceability-20180213docx|NIST GMP 13, "Good Measurement Practice +**[[https://www.nist.gov/system/files/documents/2019/06/21/gmp-13-ensuring-traceability-20190621.pdf|NIST GMP 13, "Good Measurement Practice 
 for Ensuring Metrological Traceability”]], sec. 1.1 (3rd para.):** \\ for Ensuring Metrological Traceability”]], sec. 1.1 (3rd para.):** \\
 "//Test numbers issued by NIST should not be used nor required as proof of the adequacy or traceability of a test or measurement. Having a NIST number does not provide evidence that the measurement value provided by another organization has the property of metrological traceability.//" "//Test numbers issued by NIST should not be used nor required as proof of the adequacy or traceability of a test or measurement. Having a NIST number does not provide evidence that the measurement value provided by another organization has the property of metrological traceability.//"
Line 12: Line 12:
 And And
 <WRAP center round box 80%> <WRAP center round box 80%>
-**[[https://www.nist.gov/document/gmp-13-ensuring-traceability-20180213docx|NIST GMP 13, "Good Measurement Practice  +**[[https://www.nist.gov/system/files/documents/2019/06/21/gmp-13-ensuring-traceability-20190621.pdf|NIST GMP 13, "Good Measurement Practice  
-for Ensuring Metrological Traceability”]], sec. 1.3.3, "Use of, or reference to, official test numbers of a national metrology institute":** \\  +for Ensuring Metrological Traceability”]], sec. 1.6.3, "Use of, or reference to, official test numbers of a national metrology institute.":** \\  
-"//Having an authentic test number does not provide assurance or evidence that the measurement value provided by another organization is traceable. Not only must there be an unbroken chain of comparisons, but each measurement must be accompanied by a statement of uncertainty associated with the value. Test report numbers should not be used nor required as proof of the adequacy or traceability of a test or measurement. National and international standards dealing with test and measurement quality requirements, such as ISO 10012, ISO/IEC 17025 and the ISO 9000 series do not require the use or reporting of specific test numbers to establish traceability.//"+"//Having an authentic test number does not provide assurance or evidence that the measurement value provided by another organization is traceable. Not only must there be an unbroken chain of comparisons, but each measurement must be accompanied by a statement of uncertainty associated with the value. Test report numbers should not be used nor required as proof of the adequacy or traceability of a test or measurement. National and international documentary standards for test and measurement quality requirements, such as ISO 10012, ISO/IEC 17025 and the ISO 9000 series, provide guidance for assessing metrological traceability and do not require the use or reporting of specific test numbers to establish metrological traceability.//"
 </WRAP> </WRAP>
 This is further noted in the: This is further noted in the:
Line 53: Line 53:
 Sec. 820.72 Inspection, measuring, and test equipment. \\ Sec. 820.72 Inspection, measuring, and test equipment. \\
 (b) (1) Calibration standards. Calibration standards used for inspection, measuring, and test equipment shall be __traceable to national or international standards__. If national or international standards are not practical or available, the manufacturer shall use an independent reproducible standard. If no applicable standard exists, the manufacturer shall establish and maintain an in-house standard.</WRAP> (b) (1) Calibration standards. Calibration standards used for inspection, measuring, and test equipment shall be __traceable to national or international standards__. If national or international standards are not practical or available, the manufacturer shall use an independent reproducible standard. If no applicable standard exists, the manufacturer shall establish and maintain an in-house standard.</WRAP>
 +
 +Similar antiquated language appears in [[http://everyspec.com/MIL-STD/MIL-STD-1300-1399/MIL-STD-1309D_87/|MIL-STD-1309D]], (12 February 1992), which doesn't even recognize international standards or offer alternatives where no national measurement standards exist:
 +<WRAP center round box 80%>**MIL-STD-1309D, "Definitions of Terms for Testing, Measurement and Diagnostics"**\\
 +3.1.653 Traceability. The ability to relate individual measurement results to __national standards or nationally accepted measurement systems__ through an unbroken chain of comparisons.
 +</WRAP>
  
 In contrast, ISO 17025:2017 is much more modern and technically correct in stating:\\ In contrast, ISO 17025:2017 is much more modern and technically correct in stating:\\
Line 79: Line 84:
  
 Also, while not strictly speaking a National Metrology Institute (NMI), the [[https://www.bipm.org|"Bureau International des Poids et Mesures" (BIPM)]] offers [[https://www.bipm.org/en/bipm-services/|calibration & Measurement services]] (with traceability to SI Units) to its [[https://www.bipm.org/en/about-us/member-states/|Member States]]. In that instance, the BIPM would serve as equivalent to a NMI. Also, while not strictly speaking a National Metrology Institute (NMI), the [[https://www.bipm.org|"Bureau International des Poids et Mesures" (BIPM)]] offers [[https://www.bipm.org/en/bipm-services/|calibration & Measurement services]] (with traceability to SI Units) to its [[https://www.bipm.org/en/about-us/member-states/|Member States]]. In that instance, the BIPM would serve as equivalent to a NMI.
 +
 +Transcat has an excellent White Paper on this topic at: [[https://www.transcat.com/calibration-resources/white-papers/what-is-measurement-traceability]].
 ===== What are SI Units? ===== ===== What are SI Units? =====
 {{ :articles:2018-si.png?direct&130|}} {{ :articles:2018-si.png?direct&130|}}
Line 94: Line 101:
 </WRAP> </WRAP>
  
-SI Units are also explained on the NIST web site at: https://www.nist.gov/pml/weights-and-measures/metric-si/si-units and in "[[https://www.nist.gov/pml/special-publication-330|NIST Special Publication 330 -  The International System of Units (SI)]]". Both NIST sources will likely be updated soon to reflect the new definitions to the SI that went into effect on May 20, 2019. +SI Units are also explained on the NIST web site at: https://www.nist.gov/pml/weights-and-measures/metric-si/si-units and in "[[https://www.nist.gov/pml/special-publication-330|NIST Special Publication 330 -  The International System of Units (SI)]]". 
 ===== What are "intrinsic" standards? ===== ===== What are "intrinsic" standards? =====