Documenting a Calibration Interval Extension

JohnReb

Registered
We are in the process of extending the calibration interval of a class of IMTE (small Micrometers) based on a statistical analysis per NCSLI RP1. My question pertains to the instrument labeling and certificates required for documentation. We would like to do the next calibration at the extended time period, to skip the eliminated cycle, but the instruments are currently stickered and certified at the shorter interval. Is there any experienced guidance on options for documenting the new interval, short of recalibrating every IMTE to the new interval? For example, re-stickering them would address the individual gauge identification concern, but would we also need to have all new certificates printed (they are externally calibrated)? Could we prepare a "Blanket" document stating the Serial #s that have new dates vs. those on the current certificates and record that? Of course, simply re-calibrating them to the new interval is an obvious answer, but I'd like to know if this is the only option. Any experience or accepted practices would be appreciated.
 

dgriffith

Quite Involved in Discussions
Unless you have your own database and track intervals, recalls, and print your own labels (like we have), getting them recalibrated sounds expensive just for this. I would think an approved letter on file listing the tools would do, and present it to the auditor when needed. You could also slap a label with inspector's stamp on the tool or its storage box that has the new due date. Doesn't have to be pretty until next calibration.
I don't think you need new certs, either. They demonstarte as-found/left data, with other prescribed information, except the due date. That's your business, usually. Extending the interval doesn't change the cal cert validity (since it's only valid at time of calibration anyway).
 
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JohnReb

Registered
That's basically what we are thinking, but I'm curious to know if anyone has actually passed this through an audit.
 

dwperron

Trusted Information Resource
The problem I see is that if you do not change the calibration labels on the tools you could get a finding for having the incorrect due date on the tool. Yes, you have the calibration records updated, but they can get you for having the tool incorrectly labeled.

Most of the time I see the interval being changed for each unit the next time it comes in for calibration.
 

GunLake

Involved In Discussions
Definitely change the stickers, (You can buy cheap labels online that you can hand write on, So no printer required if you don't have a label printer.) But don't worry about re printing the certificates, I would put in the notes of each micrometer in your calibration software that you extended the time period, From xx/xx/xxxx to xx/xx/xxxx. or however you'd like.
 

dwperron

Trusted Information Resource
We are in the process of extending the calibration interval of a class of IMTE (small Micrometers) based on a statistical analysis per NCSLI RP1. My question pertains to the instrument labeling and certificates required for documentation. We would like to do the next calibration at the extended time period, to skip the eliminated cycle, but the instruments are currently stickered and certified at the shorter interval. Is there any experienced guidance on options for documenting the new interval, short of recalibrating every IMTE to the new interval? For example, re-stickering them would address the individual gauge identification concern, but would we also need to have all new certificates printed (they are externally calibrated)? Could we prepare a "Blanket" document stating the Serial #s that have new dates vs. those on the current certificates and record that? Of course, simply re-calibrating them to the new interval is an obvious answer, but I'd like to know if this is the only option. Any experience or accepted practices would be appreciated.

Another question.
Have you created an internal policy regarding calibration intervals?
You will need to produce the procedure for determining the interval changes, even if it is just somebody reviewing calibration histories and determining the cycle should be longer. You will also need to document how you will change the intervals, how you will revise certificates, etc.
 

JohnReb

Registered
Thanks everyone. There is a lot of good advice here. We do have a calibration procedure that allows for the interval extension, based on a data review, and we also require verification of the cal date on each instrument at time of use, so new stickers are unavailable.
 

dgriffith

Quite Involved in Discussions
Remember labels do not have to be on instruments, especially in the case where the instruments are too small for a label to fit. The label can be on the next higher assembly or storage box or in a file as long as it’s accessible to show an auditor and reflects the current status of the MTE, which includes the new due date.
 
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