Dear Classic,
Thks for uploads.
IMO there is auditor confusion occurring over the interpretation of words like conformity, calibration as applied in different situations. Or simply nitpicking going on.
A detailed look at the limitations of the possible titles and the semantic confusions over COCo/COCa (and others) is here –
Manufacturing Calibration Certificates.pdf 106.46KB
113 downloads
eg, A comment on COCo –
So, what is a ‘Certificate of Conformance’? Typically available when an instrument is purchased, it is now generally recognized that such a document has little value as an assurance of product performance. Of course, the manufacturer expects that the product conforms to its specification but, in this sense, the document simply affirms that the stipulations of the customer’s purchase order or contract has been duly fulfilled.
Additionally, as a partial definition, - “calibration is simply the process of comparing with a known standard and reporting the results.”
So what data (and standard?) is required to be reported after a hypothetical annual “calibration” for a MD test piece ?
The answer is apparently to assure compliance with respect to BS EN ISO 9002, UKAS, AFBMA calibration requirements, eg -
http://www.metaldete...est_pieces.html
http://www.completes...est-pieces-p789
http://www.detectame...test-pieces.php
No explicit details were visible in above links. ? I hv no idea what the UKAS requirement means, AFBMA probably refers to steel ball size tolerances, we all know what iso9002 is.
Perhaps, in view of its intended usage, the test-piece certificate should contain something in respect to a standard MD’s response characteristics to the test-piece ? But in practice, none seem to do so.
The detail on Caz’s example is certainly more visually impressive than yr "certificates" (which do hv some slightly odd statements / ambiguities) together with references to iso 3290, iso9001. iso3290 appears to be another standard for dimensional accuracies of steel balls. Hmmm.
In comparison to all the above, the calibration of a reference checkweight has an obvious practical expectation other than compositional data.
All very confusing (to me) but i think you should hv challenged the auditor as to why, for example, yr C2 item was inadequate.
Rgds / Charles.C
PS (added later) – It's an interesting topic so i expanded a little. 
Just for info., here is a summary of a generic list ( ISO17025) regarding info. to be given in a Calibration Certificate (example attached at end post) -
5.10.2 TEST AND CALIBRATION CERTIFICATES
- Test Report/ Calibration Certificate shall contain
- Title (Test Report/ Calibration Certificate)
- Name & address of the laboratory
- Unique identification (like serial number)
- Name & address of the Customer
- Identification of Test Method
- Condition & identification of Test/ Calibration item
- Date of receipt & date of test/ calibration
- Reference to sampling plan, if any
- Test/ calibration results
- Name & designation of persons authorizing report
- A statement to the effect that the results relate to only the items tested/ calibrated
5.10.4 CALIBRATION CERTIFICATE
5.10.4.1 In addition to the requirements listed in 5.10.2, calibration certificates shall include the following,
where necessary for the interpretation of calibration results:
a) Environmental conditions, if applicable
b) Uncertainty of measurement
c) Evidence measurement traceability
5.10.4.2 Statement of compliance shall include which parameters of specification are met /
not met
5.10.4.3 Any adjustments/ repairs carried out shall be reported
5.10.4.4 No recommendation on calibration interval
As far as I can see, the BRC standard makes no explicit requirement regarding onward certification / calibration of the metal detector calibration standards (test-pieces) although it could be interpreted as expected within para. 4.10.3.4. However posted experiences here suggest that such a possibility is not implemented, ie auditors appears to generally accept COCos. The standard does specify shape / materials.
I have no particular expertise regarding MD test-pieces but based on previous posts, can suggest -
The minimum requirements for a Manufacturer’s Specification for the test-pieces is data regarding the size, shape and material plus appropriate assertions as to the control / traceability of the manufacturing history / process (eg involving ISO9001, traceable to National Standards).
No specific performance criteria / data seem to be required.
Regarding uploads, the C1/C2, COCos are basically asserting that the item (ie a ball) complies with the manufacturer’s specification by virtue of the data supplied and/or cross-referred to. The level of assertion is defined by the specific text.
Examining uploads –
C1
The COCo gives values for size and material for the “ball”.
The specification states that ball is manufactured to AFBMA standard (AFAIK this may cover size and composition, [see sample attached below]) (evidence in referred certificate).
The COCo does not claim the item is traceable to National Standards.
The COCo does not identify the material in “detail” (may be in referred certificate).
The COCo has a rather obscure introductory text, especially following "may" (probably due to a generic form)
The cross-referenced certificates are apparently not provided.
AFBMA standard for metal balls.pdf 1.45MB
71 downloads
C2
The COCo gives values for size and material for the “ball”.
The specification states that ball is manufactured to AFBMA standard (AFAIK this may cover size and composition, [see sample attached below]) (evidence in referred certificate).
The COCo does claim that the items are traceable to National Standards. (evidence??)
The COCo does not identify the material in “detail” (may be in referred certificate).
The cross-referenced certificates are apparently not provided.
"Con" Comments
Both COCos apparently lack the cross-referenced certificates.
Upload C1 has one significant omission (see underlined).
Whether auditor dissatisfaction was concerning lack of details, cross-certificates, age of COCo (?) only the auditor knows, so far.
Regardless, IMO / IMEX the COCo “method” should in principle be acceptable.
Note: if “Calibration Certificate” is envisaged
I predict some test-piece manufacturers happily use this title although content is not dissimilar to typical COCo. A question of interpretation. Whether will be more auditorially acceptable is another matter.
Strictly a Certificate of Calibration (eg as per ISO17025) requires inclusion of numerous items (see top list). Any COCa surely requires some statistical data further to typical COCo content evidencing that a calibration procedure has been performed for appropriate parameters, eg some uncertainty results.
A detailed example here –
Sample calibration certificate for checkweights as per ISO17025.pdf 51.19KB
44 downloads