We strongly recommend a periodic recertification of our Standards. The consensual recommended time interval is one calendar year, though individual internal requirements or requirements dictated by ISO 9001 may vary. The original certification date for each Standard appears on the Certificate of Calibration.
We also recommend recertification when the calibrated thickness of the Standard seems to have changed dramatically due to contamination or other factors.
The recertification process consists of a preliminary inspection and measurement. If no physical damage is found in the calibration area (such as pits, scratches, cracks, etc.), the standard will be chemically and mechanically cleaned. Then a complete calibration procedure will be performed. The Standard will be recertified traceable to NIST, and a new Certificate of Calibration will be issued.