The ISO 9001 Standard requires that calibrated & traceable measuring devices be used to make decisions regarding the acceptability of product. How you manage that is up to you. Identification / tagging of each device, or its storage location with the due date for calibration is the required control to prevent usage of an out-of-calibration device.

Best practice is commonly accepted to be the re-calibration prior to expiry of the calibration, but this is not mandatory. Some businesses actually set up their calibration schedule to achieve calibration over a one-month interval, instead of locking into a specific date. For example, a gauge calibrated in June of 2012 is valid until June 2013, but colour coded for calibration during July. Any gauge with that specific colour tag is removed from the production floor at the start of the month, and calibrated in the in-house lab.

Turnaround should not require a whole month. If this is the case, depending on the criticality of the gauge / measurements taken, another device may be required, and usage rotated to ensure that a calibrated instrument is always available. This is normally the case where the colour coded system described above is in use. Calibration frequencies may also require review. If you have experienced several calibration cycles without requiring any adjustment, then I suggest you are calibrating too frequently, and need to make adjustments.

ISO 17025 specifies the requirements for the operation of a calibration facility. It stipulates more detail regarding how you conduct and control the calibration activity, but does not get into scheduling particularly.

The discussion all comes down to business risk. The risk involved in running the gauge to the re-certification date is that you will miss the date, causing a review of the inspection decisions involving that instrument, with the potential of needing to recall product if gauge error could have potentially released non-conforming product. If the instruments are stable, and you can schedule production around their absence, then the Standard does not specifically require you to re-calibrate them prior to the expiry date.

Hope that helps!

– Ted Uffen, BRC Quality Consultant