Many laboratories perform simple calibrations in-house.
In such cases, the laboratories are required to maintain the necessary reference standards and equipment to ensure traceability of the in-house calibrations. To ensure compliance with the policy, the reference standards and relevant equipment must be calibrated by an accredited calibration laboratory or directly by NIST or another national laboratory. The use of control charts is recommended. In some cases, a calibration assessor may be added to the assessment team if a substantial amount of calibrations are performed in-house. This scope contains the specific parameters, ranges, associated uncertainties, and measurement techniques for which the lab is accredited.