6. Internal Calibration Procedure (Methods)
This stage is where we determine all the requirements related to the actual calibration of UUC. After inspecting the received UUC, we will now determine how we can execute the calibration job.
Actual calibration can be performed or executed by following a documented calibration procedure. Calibration procedures is a controlled document. Whether it is an ISO 17025 procedure or an ISO 9001 procedure, it is based on:
manufacturer manual or equipment manual,
based on customer recommendations,
based on experience with a similar type of equipment
based on published standard documents or guides – this is a must to have or included as a reference, more so if you are planning to apply for accreditation
or a combination of all.
After performing calibration, it is important to perform a verification. This is to check whether the results we obtain are within acceptable specifications. How to perform verification? read more in this link >> verification
If you generate your own calibration procedure, ensure that it is properly validated, meaning you have determined it to be fit for its intended purpose, and of course, it should be properly documented. Check this link to learn more about validation.
Below are the contents that we should consider in generating a calibration procedure (as a minimum). These requirements are also applicable to the ISO 9001 calibration procedure.
Title of the procedure
Scope
References
Required Instruments or reference standards (equipment used)
Step-by-Step Procedure (which includes the Test parameters and tolerances)
The uncertainty of measurements – this is one way to show traceability and confidence to our calibration results, also some auditors are requiring it.
Since it is a controlled document, we should not forget to include the author, revision number, a unique code for this procedure, the revision history, and more depending on the format in which your doc control requires you to add. Also, this generated procedure is required to be reviewed once a year or as necessary to ensure the use of an updated one.
7. Labeling and Sealing
Once the UUC is calibrated, a calibration label or tag should be placed in the UUC as a sign of calibration. This will indicate the status of a calibrated Instrument. The most used labels are stickers that contain the below information (this depends on the laboratory):
Calibration labels should be clearly visible when attached. There are times when a UUC has a limited calibration or a calibration- not-required label, this type of label should be included.
But make sure that there are proper assessments and documentation. Also, regarding the UUC with a smaller size where it is impractical to put the sticker, we can place it in its box or container.
It is also required to put a tamper-proof seal to protect the newly calibrated UUC from any unauthorized adjustments that can invalidate the calibration settings.
A calibration label printer is now available for faster and better printing of labels or stickers. More advanced calibration label printers are now available which is a fast and portable label printer that can be brought for site calibration.
