Flow meters must be calibrated annually. Which type of record should be kept?

• A. Internal records
• B. WDNR calibration records
• C. Public notices
• D. Equipment invoices

Answer: (B)

Calibration records serve as the official proof that the flow meter has been checked and kept accurate, which is essential for trustworthy process control and regulatory reporting. In Wisconsin, these records are kept as WDNR calibration records, ensuring a standardized, regulator-facing documentation trail. They typically capture when the calibration was done, who performed it, the method and standards used, the instrument’s details, the results and any adjustments, and the next due date. Having this specific record type means inspectors can quickly verify compliance and traceability. Internal records are useful for day-to-day housekeeping, but the regulator expects WDNR calibration records to demonstrate that annual calibration occurred. Public notices aren’t relevant to instrument calibration, and equipment invoices don’t confirm ongoing accuracy or calibration status.