What to check / look for in a third-party Calibration Report?

[Prasanna Kumar]

Hi,
I am working in a project as a process control engineer. I need to check the calibration certs issued by our subcontractor. Could you please let me know how to ensure that proper calibratin of the instruments has been done. The subcontractorhas got the calibration done from the third party & the report includes
NIST Std , Uncertanity level (k=2, 95% confidence level). Do I have to ask for Acuracy Ratio (TUR or TAR). Appreciate if you could let me know what to check, as I have to certify that calibration has been done properly.

Prasanna

 

[DICKIE]

You can determine the TUR yourself by appling the stated uncertainty to you part specifications. A ratio of 4:1 seems to be the direction everyone is going.

 

[Sam]

"Appreciate if you could let me know what to check, as I have to certify that calibration has been done properly."

You should NOT certify anyone on the basis of a cert. First you should determine if the lab is qualified by performing an audit to a specified standard. The audit should be performed by members of purchasing, quality and possibly engineering and Mfg.

 

[DICKIE]

I agree with Sam unless the lab is accreditted to either ISO guide 25 or ISO 17025 by a recognized body (AL2LA, NAVLAP).

 

[metrologyguy]

ISO/IEC 17025 lists specific certification requirements. The format is easy to follow and could even be used as a check list. On the issue of auditing the lab, unless your company has trained assessors, you would just be visiting the lab and looking for stickers. In todays world, assessing a lab requires a metrologist. Items to be determined at the lab : are the labs stated uncertainties realistic? how did the lab do in their proficiency testing? are theri calibration procedures consistant with other labs ?. I would on use labs accredited by A2LA (www.a2la.org).

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