After receiving calibration results, it’s important to review the calibration report to ensure accuracy. When reviewing the results, the following checkpoints should be concentrated on:
CORRECTION OF ERROR
This checkpoint is very important in regards to measuring instruments and devices and helps to identify errors and tolerance. For example, during preventive maintenance, a correction factor is determined to and then inputted on the equipment being calibration to compensate or correct the errors displayed.
This checkpoint is particularly important for understanding the total allowable error within an instrument. Tolerance is typically represented as a +/- value. Notably, instruments can become deformed due to environmental changes that lead to material expansion and contraction. For this reason, it is extremely important to review the calibration results for this checkpoint to ensure you understand the tolerance and to be able to take the allowable error range into consideration.
AS FOUND/AS LEFT DATA
These checkpoints includes data for before an instrument was calibrated and after it has been calibrated. It’s important to check this data to ensure that the measurement value lies within the limit. If your data shows an allowable limit, then your measurement value is acceptable.
Another important factor to acknowledge when checking the “as left” and “as found” data is that the “as left” column will, in some cases, differ in adjustment due to the “as found” value being outside of an acceptable limit.
TRACEABILITY AND UNCERTAINTY
These checkpoints include determining if the calibration results have calculated an estimated uncertainty ratio and if the results are traceable. If an uncertainty ratio is calculated correctly then traceability of measurements can be guaranteed. This is because during uncertainty estimation, a laboratory’s best measurement capability (BMC) is incorporated, which is acquired from a higher laboratory standard.