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--- articles:nist_traceability [2020/01/23 09:22] – [What are "International Standards"?] rrandall
+++ articles:nist_traceability [2020/04/24 08:01] – [An "unbroken chain of calibrations" to what?] rrandall
@@ Line 53: / Line 53: @@
 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>
-And [[https://www.faa.gov/documentLibrary/media/Order/6200.4G.pdf|FAA National Policy - Order 6200.4G]]" (dated 03/08/10) states:
-<WRAP center round box 80%>
-**FAA National Policy - Order 6200.4G** \\
-Appendix 2 - Definitions \\
-h. Calibration Standard - a device or instrument used as a basis to calibrate measure, gage, test, inspect, or otherwise examine basic accuracy values. The standard has a higher order of accuracy than the examined item and is __traceable to the National Institute of Standards and Technology (NIST)__.</WRAP>
 In contrast, ISO 17025:2017 is much more modern and technically correct in stating:\\
@@ Line 86: / Line 79: @@
 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? =====
 {{ :articles:2018-si.png?direct&130|}}
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 ==== Legal Metrology ====
-Fluke performs this comparison because, just as the requirements for “measurement traceability” contained in ISO 9001:2015 & AS9100:2016 (Rev. D) are antiquated, so is U.S. law in this area. U.S. Law has designated NIST as holding the national standards of measurement, and NIST has defined the U.S. legal volt to be produced from its one particular Josephson voltage system, so it is the national standard. However, this is only pertinent to the area of "legal metrology" (Ref.: [[https://www.oiml.org/en/about/legal-metrology|International Organization of Legal Metrology]]).
+Fluke performs this comparison described above because, just as the requirements for “measurement traceability” contained in ISO 9001:2015 & AS9100:2016 (Rev. D) are antiquated, so is U.S. law in this area. U.S. Law has designated NIST as holding the national standards of measurement, and NIST has defined the U.S. legal volt to be produced from its one particular Josephson voltage system, so it is the national standard. However, this is only pertinent to the area of "legal metrology" (Ref.: [[https://www.oiml.org/en/about/legal-metrology|International Organization of Legal Metrology]]).
 ===== What are "International Standards"? =====
@@ Line 171: / Line 166: @@
 **3 & 4 - VSMOW2 (Vienna Standard Mean Ocean Water) & SLAP2 (Standard Light Antarctic Precipitation)** \\
 Distributed by the [[https://nucleus.iaea.org/rpst/ReferenceProducts/ReferenceMaterials/Stable_Isotopes/2H18O-water-samples/VSMOW2.htm|"International Atomic Energy Agency" (IAEA)]] for differential stable isotope amount-of-substance ratio measurements, the [[http://www-naweb.iaea.org/NAALIHL/docs/ref_mat/InfoSheet-VSMOW2-SLAP2.pdf|VSMOW2 & SLAP2 reference material standards]] are used in producing the triple point of water (see the BIPM "[[https://www.bipm.org/utils/common/pdf/ITS-90/Guide_ITS-90_2_2_TPW-2018.pdf|Guide to the Realization of the ITS-90 - Triple Point of Water]]") with the smallest amount of uncertainty.
-===== Conclusion =====
+===== Traceability to Organizations, rather than SI Units =====
-Specifying that a calibration service provider __must__ supply "NIST Traceable" calibration certifications not only reveals a lack of understanding "metrological traceability", it ignores the reality that many calibrations, whether from NMIs (e.g., the [[https://www.nrc-cnrc.gc.ca/eng/solutions/advisory/calibration_index.html|NRC]] in Canada, [[http://www.cenam.mx/eng/|CENAM]] in Mexico, [[https://www.ptb.de/cms/en.html|PTB]] in Germany,) or accredited commercial metrology laboratories, may be traceable to SI units through other means (e.g., intrinsic measurement standards).
+The US Federal Aviation Administration, "[[https://www.faa.gov/documentLibrary/media/Order/6200.4G.pdf|FAA National Policy - Order 6200.4G]]" (dated 03/08/10) states:
+<WRAP center round box 80%>
+**FAA National Policy - Order 6200.4G** \\
+Appendix 2 - Definitions \\
+h. Calibration Standard - a device or instrument used as a basis to calibrate measure, gage, test, inspect, or otherwise examine basic accuracy values. The standard has a higher order of accuracy than the examined item and is __traceable to the National Institute of Standards and Technology (NIST)__.</WRAP>
+Specifying that a calibration service provider __must__ supply "NIST Traceable" calibration certifications, which this policy essentially requires, not only reveals a lack of understanding "metrological traceability", it ignores the reality that many calibrations, whether from NMIs (e.g., the [[https://www.nrc-cnrc.gc.ca/eng/solutions/advisory/calibration_index.html|NRC]] in Canada, [[http://www.cenam.mx/eng/|CENAM]] in Mexico, [[https://www.ptb.de/cms/en.html|PTB]] in Germany,) or accredited commercial metrology laboratories, may be traceable to SI units through other means (e.g., intrinsic measurement standards).
 This is politely pointed out by the [[https://ilac.org|ILAC – International Laboratory Accreditation Cooperation"]].
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 Source: [[https://ilac.org/?ddownload=840|ILAC-P10:01/2013, "ILAC Policy on the Traceability of Measurement Results"]]"
 </WRAP>
+===== Conclusion =====
 Unless required by statute or regulation (i.e., for [[https://www.oiml.org/en/about/legal-metrology|Legal Metrology]]), mandating "NIST traceability" unnecessarily "limits" the sources for metrological traceability, excluding other NMIs and/or accredited commercial metrology laboratories.
+NIST, for example, is a non-regulatory agency of the United States Department of Commerce. When the US Government was "shut down" during 1995, 2013, 2018, and 2019, NIST operations were suspended. So if your company had measurement standards at NIST awaiting calibration, or if you outsourced calibration to a metrology lab who had its measurement standards at NIST, then the length of time associated with the government "shutdown" was added to the delay in receiving those instruments. These government "shutdowns" create a "ripple effect" throughout industry.
+To avoid this, standards writing bodies and regulatory agencies should gain a better understanding of "metrological traceability" and allow other NMIs and/or accredited commercial metrology laboratories to be utilized in providing metrological traceability to SI units. In particular, these bodies should promote international consistency of measurements through adopting the recommendations of the [[https://ilac.org/latest_ilac_news/joint-bipm-oiml-iso-and-ilac-declaration-on-metrological-traceability-signed/|"Joint BIPM, OIML, ISO and ILAC Declaration on Metrological Traceability"]].
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 For more information visit: [[https://us.flukecal.com/literature/about-calibration]]