Calibration is a process used to maintain the accuracy of a measurement device. The calibration process involves comparing the measurement device to a known reference – the reference being highly accurate in relation to the device being calibrated.
When you buy an instrument, how would you validate the device’s accuracy level? That is where calibration certificates come in. Calibration certificates validate the device’s accuracy levels to a standardized reference.
A device's calibration must be traceable to the U.S. National Institute of Standards and Technology (NIST) or the respective national metrology institution established in your country. Calibration must be conducted by a service provider who is accredited under ISO Standard 17025.
What is a Calibration Certificate?
A calibration certificate is a document that contains information about a device’s calibration. This certificate provides valuable information on the quality and measurement accuracy of the device. The calibrations certificate is prepared based on the standards put in place by the National Institute of Standards and Technology (NIST).
It is important to note that the accuracy and calibration of a device vary based on many factors. For example, sensitive devices used in industries may need a higher level of calibration. Similarly, a measurement device used for less complex operations may not require a higher degree of accuracy. Depending on the calibration of a device, its cost also changes.
What Should a Calibration Certificate Contain?
Calibration certificates follow a certain structure. The document has various information about the device, along with the original standards. Here’s a basic structure of a calibration certificate.
- Title: The certificate name
- The details of the laboratory tasked with the calibration
- Customer details
- A unique identification code for the calibration certificate
- The device name and details
- Details on the environmental conditions where the calibration took place
- Calibration results with respective sign conventions
- Name, designation, identification, and signature of the person in charge of the calibration
- A statement that specifies these test results are only relevant to this specific device
- Evidence that the measurements are traceable
What is a Traceable Calibration Certificate?
In equipment calibration, there is one word that carries a great deal of importance – traceability. Traceability of measurement is its property where it can be related to a known reference. Without tractability, we cannot prove that measurement is correct. The formal definition of traceability according to International Vocabulary of Metrology is:
“Property of a measurement result whereby the result can be related to a reference through a documented unbroken chain of calibrations, each contributing to the measurement uncertainty.”
A properly calibrated equipment or device will be traceable to reference values. However, the traceability of equipment can change over time. In other words, the accuracy of its measurement will change over time, and this process accelerates when the equipment is under constant use. To maintain traceability, the equipment must be calibrated at regular intervals.
Calibration Standards are kept in place to ensure competence in testing and calibration. Hence, a laboratory needs to adhere to these standards to be recognized as a dependable source. Let us look at the globally accepted standards in calibration.
ISO 17025: This standard is used in laboratories that are vested in equipment calibration and testing. ISO 17025 requires traceability of measurements, demonstration of technical competence, and the application of measurement uncertainty.
NIST (National Institute of Standards and Technology) Calibration Assurance Program: The NIST standard certifies whether a laboratory is fit enough to calibrate measurement devices. The certification is only issued if the laboratory has implemented all the NIST-maintained measurement standards.
NIST Calibration Standards
There are an array of NIST Calibration Standards aimed at laboratories. You can find resources on Good Laboratory Practices, Good Measurement Practices, and Standard Operating Procedures.
How to get a Calibration Certificate?
A calibration certificate is mandatory for any equipment that finds its use in industrial, medical, or scientific applications. Since the industry demands accuracy, a calibration certificate is only issued if the equipment checks all the right boxes. OMEGA Engineering has been a pioneer in measurement devices, where our products have always adhered to the highest standards. We provide NIST traceable calibration for your measurement and control Products.
Competent, trained technicians perform all calibrations at OMEGA. Contact our Customer Service Department to discuss your specific calibration requirements.