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articles:nist_traceability [2019/05/25 12:46] – [What are SI Units?] rrandallarticles:nist_traceability [2019/11/20 07:28] – [An "unbroken chain of calibrations" to what?] rrandall
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 a. calibrated or verified, or both, at specified intervals, or prior to use, against measurement standards __traceable to international or national measurement standards; when no such standards exist, the basis used for calibration or verification shall be retained as documented information__;//" a. calibrated or verified, or both, at specified intervals, or prior to use, against measurement standards __traceable to international or national measurement standards; when no such standards exist, the basis used for calibration or verification shall be retained as documented information__;//"
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-Unfortunately, the language in ISO 9001:2015 & AS9100:2016 (Rev. D) is extremely antiquated in stating its requirements for "measurement traceability". In contrast, ISO 17025:2017 is much more modern and technically correct in stating:\\+Unfortunately, the language in ISO 9001:2015 & AS9100:2016 (Rev. D) is extremely antiquated in stating its requirements for "measurement traceability". And, unfortunately, similar antiquated language appears in U.S. Regulations. For example: 
 + 
 +<blockquote>TITLE 21--FOOD AND DRUGS \\ 
 +CHAPTER I--FOOD AND DRUG ADMINISTRATION \\ 
 +DEPARTMENT OF HEALTH AND HUMAN SERVICES \\ 
 +SUBCHAPTER H--MEDICAL DEVICES \\ 
 +PART 820 -- QUALITY SYSTEM REGULATION \\ 
 + 
 +Subpart G--Production and Process Controls \\ 
 + 
 +Sec. 820.72 Inspection, measuring, and test equipment. \\ 
 +(a) Control of inspection, measuring, and test equipment. Each manufacturer shall ensure that all inspection, measuring, and test equipment, including mechanical, automated, or electronic inspection and test equipment, is suitable for its intended purposes and is capable of producing valid results. Each manufacturer shall establish and maintain procedures to ensure that equipment is routinely calibrated, inspected, checked, and maintained. The procedures shall include provisions for handling, preservation, and storage of equipment, so that its accuracy and fitness for use are maintained. These activities shall be documented. 
 + 
 +(b) Calibration. Calibration procedures shall include specific directions and limits for accuracy and precision. When accuracy and precision limits are not met, there shall be provisions for remedial action to reestablish the limits and to evaluate whether there was any adverse effect on the device's quality. These activities shall be documented. 
 + 
 +(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.</blockquote> 
 + 
 +In contrast, ISO 17025:2017 is much more modern and technically correct in stating:\\
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 **ISO 17025:2017, “General requirements for the competence of testing and calibration laboratories”** \\ **ISO 17025:2017, “General requirements for the competence of testing and calibration laboratories”** \\
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 As mentioned earlier, [[https://www.fluke.com|Fluke]] owns a [[https://nvlpubs.nist.gov/nistpubs/jres/095/jresv95n3p219_A1b.pdf|Josephson voltage system]], which they can use to realize the SI Units directly for DC Volts. Even though they don't send an instrument to NIST for calibration, they [[https://www.fluke.com/en-us/learn/blog/electrical/the-volt-makes-a-stop-at-the-fluke-metrology-lab|compare their Josephson voltage system to an identical Josephson Voltage system maintained by NIST]].  As mentioned earlier, [[https://www.fluke.com|Fluke]] owns a [[https://nvlpubs.nist.gov/nistpubs/jres/095/jresv95n3p219_A1b.pdf|Josephson voltage system]], which they can use to realize the SI Units directly for DC Volts. Even though they don't send an instrument to NIST for calibration, they [[https://www.fluke.com/en-us/learn/blog/electrical/the-volt-makes-a-stop-at-the-fluke-metrology-lab|compare their Josephson voltage system to an identical Josephson Voltage system maintained by NIST]]. 
 +
 +==== 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 that NIST holds 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 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 that NIST holds 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]]).
 +
 +U.S. Regulations often require metrological traceability "to NIST". For example:
 +
 +
 +
 ===== What are "International Standards"? ===== ===== What are "International Standards"? =====
 While ISO 9001:2015, AS9100:2016 (Rev. D) and ISO 17025:2017 all mention "International Standards", I am aware of only four (4) "international standards" (as opposed to SI //units//); three of which are listed as examples in the "Bureau International des Poids et Mesures" (BIPM) [[https://www.bipm.org/utils/common/documents/jcgm/JCGM_200_2012.pdf|JCGM 200:2012, "International vocabulary of metrology – Basic and general concepts and associated terms (VIM)"]] (3rd edition), sec. 5.2, "international measurement standard". However, there are probably others. Those that I am aware of include: \\ While ISO 9001:2015, AS9100:2016 (Rev. D) and ISO 17025:2017 all mention "International Standards", I am aware of only four (4) "international standards" (as opposed to SI //units//); three of which are listed as examples in the "Bureau International des Poids et Mesures" (BIPM) [[https://www.bipm.org/utils/common/documents/jcgm/JCGM_200_2012.pdf|JCGM 200:2012, "International vocabulary of metrology – Basic and general concepts and associated terms (VIM)"]] (3rd edition), sec. 5.2, "international measurement standard". However, there are probably others. Those that I am aware of include: \\
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-Unless required by statute or regulation (i.e., for Legal Metrology), mandating "NIST traceability" unnecessarily "limits" the sources for metrological traceability, excluding other NMIs and/or accredited commercial metrology laboratories.+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.