The process of confirming, through objective evidence, that specified requirements have been fulfilled. In metrology, verification checks whether an instrument meets its stated accuracy specifications.
Verification is a confirmation that an instrument or measurement system meets defined specifications. It differs from calibration in that verification produces a pass/fail result against established criteria, while calibration determines the actual measurement errors and associated uncertainties. Verification may be performed as part of a calibration process (when the as-found data is compared against tolerances) or as an independent check.
In practice, verification can range from a simple functional check to a comprehensive evaluation. Examples include checking a thermometer at the ice point, verifying a balance with a known check weight, or performing an intermediate check on a reference standard between scheduled calibrations. Intermediate verifications are a key element of ISO 17025 quality systems, providing evidence that equipment continues to perform acceptably between full calibrations.
For calibration management, verification serves as a risk-reduction tool. Regularly scheduled verifications between calibrations can catch drift or problems early, before they affect product quality. Verification results should be documented and trended, and out-of-specification verification results should trigger immediate investigation and recalibration. Many organizations establish a verification schedule that is more frequent than the calibration schedule, using simpler checks to maintain confidence in instrument performance.
In an aerospace calibration lab, verification occurs when a newly calibrated torque wrench rated for 50 ft-lbs is checked against acceptance criteria of ±2% accuracy. The technician applies known loads at 10%, 50%, and 90% of range, comparing actual readings to reference values from a deadweight tester traceable to NIST. If readings fall within ±1 ft-lb at all points, verification confirms the wrench meets specifications. In a medical device manufacturer's lab, verification of a digital thermometer involves checking it reads 37.0°C ±0.1°C when placed in a calibrated temperature bath at body temperature. The thermometer must consistently display 36.9-37.1°C to verify it meets FDA requirements for clinical use. Getting verification wrong causes significant problems: An aerospace supplier failed to properly verify pressure transducers, leading to readings 3% outside specification limits. This resulted in incorrect fuel system pressures during flight tests, triggering a costly investigation and delayed aircraft delivery. During the subsequent AS9100 audit, auditors found the lab had calibrated instruments but failed to verify they met customer requirements, resulting in a major nonconformity and suspended certification until proper verification procedures were implemented.
ISO/IEC 17025:2017 Section 7.8.4.1 requires laboratories to verify that calibration results meet specified requirements and demonstrate measurement uncertainty is adequate. AS9100D Section 7.1.5.2 mandates verification that measuring equipment capabilities are suitable for intended measurements. ISO 13485:2016 Section 7.6 requires verification that measuring equipment can achieve required measurements with necessary precision. IATF 16949:2016 Section 7.1.5.1.1 demands verification of measurement system capability studies. ISO 9001:2015 Section 7.1.5.1 requires verification that measurement resources provide valid results. ANSI/NCSL Z540.3-2006 Section 9.2 specifies verification requirements for calibration certificates. During audits, auditors examine calibration records to confirm verification was performed against stated specifications, look for documented acceptance criteria, verify measurement uncertainty was considered in verification decisions, and check that out-of-tolerance conditions were properly identified and addressed. They specifically review whether the lab demonstrated that calibrated instruments actually meet customer requirements, not just that calibration was performed.
CalibrationOS handles verification through its Acceptance Testing module, which automatically compares calibration results against pre-defined acceptance criteria stored in instrument records. The system captures verification status (Pass/Fail) for each measurement point, calculates conformity ratios, and flags instruments that fail verification requirements. The Certificate Generator automatically includes verification statements confirming instruments meet specifications, with detailed measurement data and uncertainty analysis. During audit preparation, the Compliance Dashboard provides verification statistics and identifies any instruments with failed verification status. The system maintains complete verification history, enabling auditors to review verification decisions over time. Risk Assessment tools help determine appropriate verification intervals based on instrument stability and criticality. Integration with the Uncertainty Calculator ensures measurement capability is adequate for intended applications, supporting verification decisions with quantitative evidence that satisfies ISO/IEC 17025 requirements.
Verification is the process of confirming that a measuring instrument meets its specified requirements by comparing its performance against defined criteria. It produces a pass/fail result rather than the detailed error analysis provided by calibration.
Verification checks are typically performed more frequently than full calibrations — daily, weekly, or monthly depending on the instrument's criticality and stability. They serve as early warning checks between scheduled calibrations.
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