The comparison of measuring equipment against a standard instrument of higher accuracy is known as calibration. It is performed to detect, correlate, adjust, rectify and document the accuracy of the equipment under test. Periodic calibrations are required to detect and correct the error. Periodic calibrations are an integral part of any quality system.
Instrument calibration is used to maintain instrument accuracy and to configure an instrument to obtain a result of a sample within an accepted range. When purchasing new testing equipment, it comes with a certificate confirming its calibration before leaving the manufacture. Re-calibration is important to maintain the accuracy of the equipment throughout its life. In order to obtain reliable results, proper equipment calibration test is necessary.
Some Dos and Don’ts of calibrating equipment:
Factors to Focus
Several factors should be taken into account during and after a calibration to avoid potential error sources that give rise to inaccurate results.
1. Using Precise Calibrator Values: It is imperative to follow the instructions closely. Using wrong calibrator value will result in producing significant errors over the entire operating range. Disregarding the instructions result in inaccuracy of the results.
2. Tolerance: Every calibration should be performed to a specified tolerance. Owing to the normal variations in the instrumentation and quality control process, every calibrator is associated with a tolerance. When formulating tight tolerance specifications based on manufacture’s specifications, one should focus on other factors including the requirements of the process, availability of test equipments, consistency with similar instruments at the sources etc.
3. Accuracy Ratio: It is the term that describes the accuracy of the test standard and the accuracy of the instrument under test. While calibrating an instrument, ensuring 4:1 accuracy ratio is a thumb rule. It means, the standard instrument should be at least four times more accurate than the instrument under test.
4. Traceable Standards: Traceability is another factor to look for when calibrating equipment. It is mandatory to perform all calibrations traceable to nationally or internationally recognized standard. This can be achieved by using higher level reference standards during routine calibration of equipments.
5. Uncertainty: Uncertainty analysis is performed to evaluate the factors that affect the accuracy of calibration.
The Don’ts of Calibrating Equipment
One should avoid
1. Using wrong calibrating values
2. Following non-traceable standards
Significance of Calibrating Services
All measurement devices regardless of whether measuring a milligram in the lab or a ton in a plant require calibration invariably. Accuracy of measurement can not only affect the productivity but also safety of the workers. Therefore, calibration of equipments is a necessity and calibration services can ensure that accuracy of the instruments. Calibration services can perform all sorts of calibration such as electronic calibration, pressure calibration, pipette calibration services, etc.
Since calibrating process can vary from machine to machine, it is not worth investing in so many calibrating equipments that are extremely costly. Calibration services can be the ideal solution. There are number of professional companies offering calibration services. Companies such as RS Calibration rely on their own calibration instruments that are checked for accuracy under regulated conditions so that it can meet with compliance bureau guidelines. They hire certified, licensed professionals having knowledge of calculations that guarantee accuracy. Thus, instead of spending huge amount, outsourcing calibration service is more cost effective to gauge accuracy of instruments.
Edward S stresses on the need for periodic equipment calibration to ensure accuracy of laboratory results and safety at workplace. He emphasis equipment calibration test should be conducted properly following rules and regulation. Edward also recommends outsourcing pipette calibration services and other equipment calibration jobs to professional service providers. For more information on the subject, visit RS Calibration.