Calibration Certificate

A complete, legitimate calibration certificate must include: (1) instrument identification — make, model, serial number; (2) calibration date; (3) procedure used; (4) reference standards with their own traceability documentation; (5) as-found readings before adjustment; (6) as-left readings after adjustment; (7) measurement uncertainty; and (8) certifying technician name and signature. Certificates that omit as-found/as-left data or cannot identify reference standards should not be accepted for compliance purposes.

Verify four elements: (1) the certificate identifies reference standards with their own traceability documentation; (2) both as-found and as-left readings are shown — not just a pass/fail result; (3) the certifying technician is identified by name; (4) measurement uncertainty is stated. A certificate showing only a 'passed' notation without measurement data is a sign of paper-whipped calibration and should not be accepted for audit or compliance use.

A calibration certificate documents the instrument's condition on the calibration date — it does not expire like a license. However, most compliance programs specify a maximum calibration interval (typically 12 months for field instruments), after which the instrument must be recalibrated before documentation is considered current. Using an instrument outside its required interval may invalidate the work record it is used to support.