I am trying to clearly understand the ISO 9001:2008 requirement for Control and Monitoring of Measurement Equipment. My question:
If a measurement equipment like a Karl Fisher Titrator or pH meter which is calibrated by the user with a known standard traceable to an international standard, then does the unit itself require to be periodically sent to a third party for calibration? It is not clear to me. In the past I have received a finding for not doing so. As I read the standard it is not clear. Can you provide exactly the clause and reference statement that would indicate and clarify its meaning.
Your question leads me to believe there was a valid reason for the finding you received. Calibration of a Karl Fischer Electrometric Titration unit is more of a validation and adjustment. That is, in one common practice, you use sodium tartrate dehydrate in a very fine powder form, along with other substances and follow all the steps of calibration. However, (this is why sending your unit to a third party becomes necessary), you cannot be certain your unit is reading accurately if it hasn’t had a certified calibration by a third party. Example: Is the water equivalent (WE) of the titrant (Karl Fischer reagent or titrating solution) based on accurate calculations?
If you have a known standard which is traceable to national standards which you can use as a comparator, you might be able to set your recalibration periods fairly far apart. This would of course save you money. Nonetheless, unless you can show traceability of your Karl Fischer system, you are not compliant with the standard.
That was a good question and I hope this will help.
Bud Salsbury, CQT, CQI
For more on this topic, please visit ASQ’s website.