A company maintaining quality system according to ISO 9000 quality standards must have defined procedures for controlling and calibrating its measuring equipment. Such procedures are needed to demonstrate the conformance of the final product to specified requirements. The company should:
- Identify the required accuracy and select appropriate equipment for measurements.
- Establish calibration procedures including a check method and acceptance criteria.
- Calibrate the equipment at prescribed intervals against certified equipment having a known valid relationship to nationally recognized standards. In cases where no such standards exist, the basis used for calibration must be documented.
Vaisala verifies the calibration of all delivered instruments according to a procedure similar to the one described in Refractive index nD verification.