Guides and Articles
Calibration Certificates: Connecting the Instrument With Its Measurement Record
Understand a calibration document, instrument identity and result information, and distinguish measurement records from blanket product approval.
Photo credit
A calibration certificate records identified calibration work. It connects the document with the instrument and the measurement service performed. A certificate title alone says less than the actual item and result information it contains.
Identity and the Work Recorded
An instrument model and the individual device are different references. A business with several similar instruments needs each record connected with the right item. The date and described work provide further context.
For example, a certificate for one gauge should not silently become the record for every gauge of that model. Likewise, a later repair record describes different work from the earlier calibration.
Values and Uncertainty
NIST describes its calibration reports as recording measured values and associated uncertainty for the identified item at the time of the work.
A result value and the information qualifying that result need to be read together. The laboratory can explain its document’s terms; the customer should not need to infer them from a label attached to the equipment.
Photo credit
Traceability and the Intended Use
NIST’s policy distinguishes traceability of a measurement result from automatic fitness for a particular purpose. A reference name is not a blanket approval of every later use.
The useful question is how the recorded information relates to the customer’s measurement need. That is different from treating a certificate as a product endorsement.
Service and Document
Equipment calibration is the work. The certificate is its record. Repair, adjustment and additional testing need to remain identifiable rather than be assumed from the document’s heading.
Test reports record another kind of laboratory project. A document describing product testing and one describing an instrument’s calibration have different purposes.
Certificate Questions
Does a certificate cover every instrument of that model?
No. The individual item needs to be identified.
Does it mean the instrument was repaired?
Only if that separate work is recorded.
Who explains an unclear entry?
The issuing calibration laboratory, with the instrument and document reference available.