The Ten-Point Checklist customer must check against Calibration Services to ensure a successful calibration
1. Use an accredited laboratory: Accredited labs are
required in many industries and must submit to regular technical audits. They
also have publicly available "scopes of accreditation" that provide
transparency and traceability in calibration.
2. Check if capability is acceptable: The scope of
accreditation lists what the lab is accredited to calibrate, over what range,
and their calibration measurement capability (CMC). This helps assess how good
a lab is for a specific calibration.
3. Define tolerance limits: Most dimensional measuring
equipment is calibrated to manufacturer specified tolerance limits, but
end-users can define their own tolerance limits. The tolerance limits can be
compared to the CMC of the lab to determine the Test Uncertainty Ratio (TUR).
4. Request a statement of conformity (pass/fail): While
ISO/IEC 17025 recommends calibrations following methods from published
standards or as specified by the manufacturer, it is optional in accredited
calibrations. Discounted calibrations often mean less rigorous methods,
increasing customer risk.
5. Request as-found results: As-found results determine
the stability of measuring equipment over time and are used to adjust the
calibration interval. Many calibration providers offer optional results, so it
is important to request them.
6. Adjustments and maintenance: Customers should request
adjustments and maintenance as needed, as the international definition of
calibration does not include these aspects. For accredited calibrations, the
calibration due date can only be provided on the certificate with customer
agreement.
9. Request an accredited certificate: Some accredited
labs charge extra for an accredited certificate, but a non-accredited
certificate from an accredited lab is the same as using a calibration provider
that is not accredited. To avoid confusion, be certain to request an accredited
calibration certificate.
10. Rules for calibration labels: There is limited
guidance or rules on what needs to be done in calibration for a new calibration
label to be applied. If organizations have their own internal rules, a new
calibration label may be applied with different expectations, which can be
problematic. If the idea of non-conforming equipment still receiving a new
calibration label is concerning, it is essential to define the expectations.