Instrument Calibration Requirements - Determining what affects quality

[matthew evans - 2002]

INSTRUMENT CALIBRATION

Under ISO9000:1994 it states that under clause 4.11.2 (b) Identify all inspection,measuring.......calibration shall be documented.
After reciently moving companys and starting to carryout supplier development as required in QS9000 I came across a supplier that calibrated everything he used to measure in case it "Affected quality" even tapes and rules.
Using experience from my previous company who are registered by NQA I sergested that any equipment that was used that did not have any direct effect on product quality could be marked in some way and a paragraph entered into the procedure manual stating this equipment was for reference only.
He seemed more than happy and agreed.
After his company was assessed against ISO9000 by Lloyds they advised him that this was not possible for inspection or measuring equipment and that every piece of measuring equipment must be identified (agreed) calibrated and recorded.(not agreed).
Can anyone advise me as to which way to go for future reference.

 

[Jerry Eldred]

One method I have used is "FOR INDICATION ONLY" labels on those measuring instruments which do not affect quality. But I try to be VERY conservative as to what I allow to have that label. I documented that label in the calibration policy. Definition of the label was something to the effect that readings on this instrument are non-quantitative. For example, a current meter on an installed power supply, where the current level is not used, only to 'indicate' a relative value. As far as verifying tape measures (not calibrating, as they cannot be adjusted). You'll have to scrutinize each instrument given an "INDICATION ONLY" status. You have to prove to an auditor that you don't care about the readings, they are only for reference by the user.

On the flip side of this, any portable or handheld instruments used on anything that can in any way, directly or indirectly, impact product quality must be calibrated. If a tape measure is used to measure something on the packaging, for example, it must be verified. If a DMM is used to maintain production equipment, it must be calibrated. If it is measuring equipment, my experience is that you have to use reverse proof (prove that it can not possibly directly or indirectly) affect product quality. If you can't "prove" that it "can't" affect product quality, lean toward calibrating it. Any handheld portable instrument, such as DMMs, oscilloscopes, calipers, micrometers, etc, including all of those portable test equipment that normally are calibrated, you'd really have to convince the auditor.

As for tape measures, rulers, etc.
if they are located in a production or service area that supports production or test, or shipping or receiving, it would be the same story. If they don't matter to product quality, and they are located in one of those above areas, that means that they could be thrown away with no detriment to the product or process. That's kind of a laymans way of looking at that one. I think the auditors position may be that anything that can make a measurement that is located in one of those above areas, by definition, affects product quality. The only exception being those installed monitors that you can't practically remove. Even some of those, you'd have to show evidence that they don't affect product quality.

Hope this is of some help.

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