Instrument Identification, Status and Records

Each thermometer, scale, pH meter, water-activity meter and logger needs a stable identifier that follows the device rather than only its room or operator.

Labels or electronic controls should show whether the instrument is in service, due, restricted, quarantined or out of service. The status must be legible and protected from casual alteration.

Record instrument type, range, resolution, location, owner, reference method, interval, last result, due date, repairs and disposition of failures.

When an instrument fails a check, determine when it may have become unreliable and which batches or decisions depended on it. Adjustment alone does not close the product review.

Working instruments may be checked against reference devices or materials with documented traceability and appropriate uncertainty. The reference itself also requires controlled status.

Review due lists, prevent unauthorised substitution and link critical readings to instrument identity. Retain certificates and internal checks for the period required by the quality system.