Whether you have accredited calibrations or traceable calibrations performed on your equipment, you will always receive a calibration certificate when you return your instruments. The calibration certificate contains crucial evidence of the test equipment’s integrity and the calibration’s validity.
Why is Calibration Necessary?
Critical performance gradually degrades as instruments age, change temperature and mechanical stress, or are used frequently.
This is commonly known as drift, and when that happens, test results obtained become unreliable.
Drift happens naturally, but it can be detected. By calibration, it can bring the equipment back to its standards for reliable measurement data.
Calibration is defined as a performance comparison against a standard of known accuracy. It may involve the determination of the deviation from nominal or include correction to minimize the errors.
Types of Calibration Certificates
When calibrations are performed, the certificate or report is the end product. It represents the only tangible evidence of the service that the purchaser can link to the expenditure. Not only does it show the results obtained across the scope of testing, but it’s also a necessary means of judging the calibration provider’s service quality with the data provided.
Most calibration laboratories offer several certificate forms, but the apparent similarity in their names can be confusing—Certificate of Calibration, Certificates of Verification, or Conformance. Calibration laboratories offer several forms of certificates depending on what your specific needs are. For example, calibration confirms that it is accurate. In contrast, verification ensures that your equipment does what it’s designed to do correctly.
Certificates of Calibration Will Include
While the form and content of calibration certificates vary, an adequately accredited certificate must contain the specific minimum information that assures compliance with ISO/IEC 17025 requirements.
- Identification of the Calibration Lab – A calibration certificate must identify where the calibration was performed.
- Title – Endure the document is a ‘Certificate of Calibration’ or ‘Calibration Certificate.’
- Unique Identifier – Each Certificate of Calibration is unique and should have a unique identifier such as a serial or certificate number.
- Identification of the calibrated instrument – The calibration certificate should identify the device, including a serial number and model information.
- Environmental conditions in the laboratory environment – At a minimum, the temperature and relative humidity that the calibration performed should be specified.
- Date of Calibration Identification of the calibration method used – Any calibration should be performed following an established and approved procedure.
- Traceability evidence – Traceability is a primary purpose of a calibration certificate, and proof of traceability must be documented.
- Calibration results – A calibration certificate must document the actual instrument readings against the reference values and indicate whether the instrument readings were within the tolerance of the reference standards.
- Name, title, and signature of the person performing the calibration
- Accuracy Statement – The certificate must specify the uncertainty that the instrument has been calibrated. This is often identical to the manufacturer’s specifications but may be limited by the capabilities of the calibration lab.
- Accreditation body logo/information – For certificates not issued by the manufacturer, a logo or identifying information from the body accredited the lab should be present.