Calibration Void Seals on Internal Equipment


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Does anyone have a good procedure for dealing with internal equipment for a calibration laboratory and the use of calibration void seals? I obviously have one in place, but the verbiage is confusing when it comes to cal void seals. Is the equipment taken out of service and verified by a manager? If so how does that manager verify the instrument? Or should be do away with cal void seals on all of our internal equipment to prevent any further issues?



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Re: Cal Void Seals on Internal Equipment

Furthermore - - - how about placing "Limited Calibration" printouts on instruments - such as a decade box etc etc with corrected charts?


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I have worked with this very issue often. There are common sense rules. If a military lab there are procedures.

A cal void is exactly that. If broken, the instruments calibration is now suspect and must be recalibrated to have confidence. There are many reasons why it may be broken, but it must be recalibrated before being used as a standard.

Limited cal is a reality. That an instrument is limited cal is not an issue in itself, but the specifics must be noted (e.g., AC Volts on 1000v range OOT), and detailed information available in the records. Limited cal stickers - to me - SHOULD be a different color, and if potentially hidden normally, then hand a tag on the front, or a small sticker of same color so the tech knows to look.

Hope this helps.


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This, from our metrology document:
X.x Tamper Proof Seals

"Ensures users do not reset adjustments or potentiometers that are sealed with tamper seals (e.g. 'Void When Seal is Broken" label, wax seal, lacquer seal, gage coat, etc.). Any calibrated asset discovered with a broken tamper seal will be considered uncalibrated, removed from service and submitted for evaluation."

Of course, the reason for the seal is that the equipment is uncontrolled after it leaves the lab. Hershal is right, it's a confidence issue for users and management, whether it be a standard or end-user line tool.
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