Standards Myths

MYTH	TRUTH
—Standards—
ISO17025 states that it's equivalent to ISO9000 so ISO9000 must be equivalent to ISO17025.	ISO17025 does indeed state, in its Introduction and in paragraph 1-6, that compliance with the standard means that the laboratory's quality system for their calibration or testing activities also meets the criteria of ISO9001/2. Two points to emphasize though: The activities of many service providers extends beyond just calibration or testing (e.g. repair, supply of parts, training, etc.) where 17025 does not apply. The equivalence is to the 1994 version of the ISO9000 standards which was superseded in late 2000.
My factory's quality system complies with ISO9000 so all my equipment must be calibrated "Before & After"adjustment.	A calibration service that provides assessment of the product's performance on-receipt and, if necessary, after adjustment or repair has been completed has two purposes. It enables analysis of the equipment's stability over time. More significantly, if the on-receipt performance did not meet the user's accuracy requirements, an investigation of its impact can be triggered that may result in product or work recall. These possibilities need only apply to equipment affecting the quality of the factory's product or service, for example that used for alignment or end-of-line inspection. Understanding the distinction can save a lot of money !
Accreditation agencies define the extent of testing for various products so that users can have confidence in their equipment's overall performance.	In some countries there are national and regulatory standards that are applicable to some measuring equipment. These usually relate to legal metrology (i.e. measurements made in the course of consumer trade) or statutory codes (e.g. safety) or certain sectors of industry. However, accreditation bodies do not stipulate that these must be used although labs would generally do so where applicable. Also, there are no standards concerning the typical general purpose instruments that may be used in the electronics industry, for example. Although accreditation criteria includes a need for calibration certificates to draw attention to limitations in the scope of testing performed versus the product's capability, it is left to the client and supplier to agree the content of the service. Whether the calibration utilizes any recommendations of the equipment's manufacturer is part of this negotiation.
My calibration supplier is ISO17025 accredited so all the calibrations they undertake meet that standard.	The results of a calibration performed under the scope of the accreditation are reported on a certificate bearing the authorized brand-mark of the accreditation program. For commercial reasons, most accredited laboratories offer at least two calibration service levels -- a certificate with the accreditation logo or a company-proprietary certificate. The processes used to undertake the calibration and the extent of testing may be the same in both cases, or may differ. Some accreditation programs allow the inclusion of (a minority of) measurements which are not within the lab's accredited capability, providing they are clearly identified as non-accredited.
Results which are simply reported as "Pass" or "Fail" are not acceptable.	Recording of numerical measurement data is not relevant for some tests. This may be because it's of the "go, no go" type (e.g. checking a bore using a plug gauge) or because the test procedure establishes known test conditions and looks for satisfactory response in the unit-under-test (e.g. checking input sensitivity of a frequency counter by applying a signal whose amplitude equals the specified sensitivity and noting whether stable triggering is observed). To summarize, pass/fail is valid where the decision criteria is defined (i.e. specification limits).
A supplier that has an ISO9000 certificate is good enough.	This may be reasonable but questions concerning the scope of the certification should be asked. If the quality system that was assessed related to a company's pressure sensor manufacturing operation in Chicago, how much assurance does that endow on micrometer service at their Dallas repair office? Possibly none! The scope of registration is explicit in coverage.
Only accredited calibrations are traceable to national standards.	Traceable measurements are those supported by records that can demonstrate an unbroken series of calibrations or comparisons against successive standards of increasing accuracy (reducing uncertainty) culminating in a recognized national metrology institute. Measurement traceability is, of course, also reviewed as part of an ISO9000 quality system certification.
My own testing laboratory is accredited against ISO17025 so our instruments must be calibrated at an accredited lab.	This may depend upon the interpretation of the standard by the particular accreditation body. Clause 5-6-2-1-1 of ISO17025 does not actually stipulate that traceability must only be obtained from an accredited facility only that the supplier "can demonstrate competence, measurement capability and traceability". The British accreditation agency has confirmed that it will not add supplementary requirements to the 17025 criteria. It also accepts the possibility of traceability to a non-accredited source provided that sufficient evidence is available to UKAS to confirm that the supplier complies with the standard and that the lab being audited by UKAS has the critical technical competence to make such an assessment.