Traceability - NIST Policy on Traceability, Section II.B.4

[Hershal]

I have created this thread in response to a suggestion by Jane_Ackerman. Thanks for the idea, as this is a great topic to explore.

Her note in the pressure gage thread:

Hershal,
If the calibration provider is indeed accredited, and you have their cert and scope on file, why would the NIST numbers they provide, not be valid to prove their traceability?

Isn't that part of the "credibility" of being "accredited" (ie: aren't they audited for that by their AB)?

(May need to be a separate forum topic)

Jane


My response follows.....

According to the NIST Policy on Traceability, Section II.B.4, the "NIST numbers" are job numbers.....

"Test report numbers issued by NIST are used solely for administrative purposes. Although they often uniquely identify documents that bear evidence of traceability, test report numbers themselves do not address the issues listed in II.B.1 above, and should not be considered as the sole evidence of traceability."

NCSLI also has a position on the numbers.....

"Test report numbers issued by the National Institute of Standards and Technology (NIST) of the United States Department of Commerce are intended to be used solely for administrative purposes. Although they are often used to uniquely identify documents which bear evidence of traceability, test report numbers should not be used nor required as proof of the adequacy or traceability of a test or measurement."

All of which means that NIST numbers may be used as a COMPONENT of the traceability path, but then it MUST be tied to a SPECIFIC calibration at a specific time/place, under specific conditions, for a specific customer.

To use the NIST numbers then means you will need a copy of the individual report that goes with that specific calibration of the instrument. And if the report does not document the specific calibration of the specific instrument, then it is not valid for traceability, any more than a generic calibration procedure is.

Hope this helps.

Hershal

 

[Hershal]

I neglected to answer that the AB should have checked the traceability path.....and documented it adequately.

Hershal

 

[jane_ackerman - 2010]

To use the NIST numbers then means you will need a copy of the individual report that goes with that specific calibration of the instrument. And if the report does not document the specific calibration of the specific instrument, then it is not valid for traceability, any more than a generic calibration procedure is.

Hershal

I just want to make sure I have a clear understanding (and personally, I am concerned about TS16949 compliance).
In advance, please pardon my ... I'm anticipating answers that I don't want to hear.

I send thread gages to an A2LA Accredited Company (Company A) for calibration. I have their A2LA Cert and Scope on file.

Company A's cert for my thread gage calibration lists the Manufacturer, Description, Gage ID, Serial Number, Last Cal Date, Next Cal Due Date, Uncertainty and NIST Numbers of the standards they used to calibrate my threads.
There are also some general statements at the bottom claiming traceability to Grand Masters certified by NIST and that the calibration was performed in compliance with ANSI/NCSL Z540-1, ANSI/ASME B1.2, ANSI/ASME B1.22M and ISO 10012-14

My interpretation of what you stated, is that this is not acceptable and I should be asking Company A to provide certs showing that each of their standards used, were calibrated by Company B (whoever calibrated their standards).

If this is correct, then what about the standards that Company C used to calibrate Company B's equipment?
Do I need to track down Company C, D & E etc? And how do I know that these standards are within the calibration scope for these companies unless I obtain copies of those too?

Where does it stop?

I neglected to answer that the AB should have checked the traceability path.....and documented it adequately.
Hershal

Why then, do "we" need to duplicate the work that the AB does during their registration/accreditation audit? ... and if their AB finds an issue, then my guess is, they would not receive their accreditation in the first place?


*big deep breath* .... ok, I'm done.
I hope I'm wrong so I can go eat some crow after I pull my foot out of my mouth.

 

[Hershal]

No sweat on the frustration aspect.....it is similar from here.....

At the end user (lack of a better term) you should not have to do anyhing more if you have the cert and scope from the lab and the cal cert has the logo.

The lab on the other hand gets to jump through hoops.....as does the accrediting body.....

The unpleasant reality is that in certain specific areas of calibration, NIST will ONLY give the NIST numbers.....which means they only provide job numbers, thus short-changing the labs (in my opinion of course).....

You have complied with the part you need to do.....labs and ABs have a constant challenge though.....one way a lab MIGHT handle it is to go to another NMI (National Measurement Institute) such as NRC (Canada) or CENAM (Mexico), both of whom do excellent work, are equally acceptable - oh, and they provide an ACTUAL traceability path!

In this case I provided the information.....and hopefully an outlet for some steam.....

Hershal

 

[jane_ackerman - 2010]

WHEW!!!!! Thanks for that info. I thought my job just quadrupled (or more).