Calibration Certificates - Contents and Uncertainty

[Marc]

Subject: Re: Q: Certificate of Calibration/Guerra/Naish
Date: Mon, 26 Oct 1998 10:50:29 -0600
From: ISO Standards Discussion

Subject: Re: Q: Certificate of Calibration/Guerra/Naish

I am surprised that you would get a non conformance when it comes from the manufacturer. I have worked with a number of companies and at least 9 registrars who have not given any of the 75 companies we have worked with a non conformance for this.

As far as an accredited lab versus a manufacturer being better, there are good and bad in both. But some manaufacturers such as Starrett are accredited by Navlab here in the USA.

When approaching the amount of imformation that is required, if you get a copy of quide 25 it is easy to understand and helps with knowing what is needed for calibration. However, another approach is to obtain a copy of the ISO certificate from the manufacturer as well as any other certification they have. If you have an internal supplier qualification form have them complete it as well. The using the supplier qualification process and history from previous performance (as demonstrarted the first time you sent the equipment out for calibration or the hard data sent by them) you can place them on a dock to stock plan with their certificate of conformance along with their catalogue or data sheet as meeting the requirement until you send it out the first time for calibration.

The uncertainty of the instrument is based upon the catalogue or data sheet which will tell you it is within a tolerance. As long as that tolerance provides you with the accuracy you need, and they have provided a certificate of assurance that they have met it and that it meetss international standards you should be able to pass your audit. If you ask for them you can sometimes get a copy of the procedures used by the manufacturer so as to show your registrar the method the manufacturer is using.

I can also send you a sheet with the information that you should be seeing on the certificate after you send it out. You can email me direct if you would like a copy.

Phyllis Naish

[Marc]

Subject: Re: 4.10.6
Date: Fri, 3 Sep 1999 11:39:21 -0400
From: Philip Stein
To: eric@CAM.ORG, "MacNeil, Daryl"

At 11:12 AM -0400 9/3/99, Eric Stern wrote:
>4.10.6.5 says:
>"The laboratory shall use test and/or callibration methods ... which meet the
>needs of the customer and are appropriate for the tests.... The laboratory
>shall
>verify its capability to perform to the standard specifications before carying
>out such work...."
>
>Therefore the anser is: it depends.
>If the customer agrees,
> if it is appropriate for the tests,
> verfiy capability to the standard specification
> This can mean callibration with traceable standards,
> round-robin tests, whatever is appropriate
> for the specific test
>
>Additionally, 4.10.6.2 prescribes: "The personnel making professional
>judgement
>with reference to testing ... shall have appropriate background and experience
>(both theoretical and recent practical experience).
>
>The conclusion: you need to meet both requirements.
>
>In practice, most ASTM standards have repeatability and bias statements
>arrived
>at by round robin tests that can give you some indication about the capability
>of the test
>
>--

Just a quick warning...

The 'new' way of reporting uncertainty speaks neither of bias nor repeatability, but only uncertainties of type A and B. The world is moving away from these very common, old, and unfortunately often misleading terms.

Philip Stein
Consultants in the Physical Sciences, Measurements, and Quality
Fellow, American Society for Quality, and Member of its Board of Directors
Past Chair, ASQ Measurement Quality Division, A2LA Assessor
Check out www.metrology.org , www.hamvention.org and of course, www.measurement.com
-------------------
Comments folks?

[Marc]

Subject: RE: (no subject)
Date: Fri, 3 Sep 1999 08:36:08 -0300

Roger,

I'm no expert...but from my experience you may have to prove competency of personnel if the work they are doing must be certified (i.e. welding, engineering, etc.)...otherwise your training program should ensure how your company trains it's employees to complete their jobs. I'm not sure what you mean by "round-robins", but in general you have to ensure that you can meet the requirements of the contract - so if the contract asks for welding to a certain spec - then you have to prove that you have the technology and the personnel to do that.

HTH,
Daryl

---------snippo--------

Will someone please explain Round Robins to me! Thanks in advance!