Whether you have accredited calibrations or traceable calibrations performed on your equipment, you will always receive a calibration certificate when you get your instruments back.  The calibration certificate contains crucial evidence of the integrity or test equipment and the validity of a calibration.

Why is the Calibration Necessary?

As instruments age and undergoes changes in temperature, mechanical stress, or used frequently, critical performance gradually degrades.  We commonly know this as drift, and when that happens, test results obtained becomes unreliable.  Drift happens naturally.  However, it can be detected, and by calibration, it can bring the equipment back to its standards for reliable measurement data.

They specifically define calibration as a performance comparison against a standard of known accuracy.  It may just involve the determination of the deviation from nominal or include correction to minimize the errors.

Types of Calibration Certificates

When calibration performance takes place, 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 key means of judging the quality of the calibration provider’s service with the data provided.

Most calibration laboratories offer several forms of the certificate, 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.  Calibration confirms that it is accurate.  Whereas verification ensures that your equipment is doing what the design intends it to do correctly.

Certificates of Calibration Will Include

While the form and content of calibration certificates vary, a properly 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.  It should have a unique identifier such as a serial or certificate number.
• Identification of the calibrated instrument – The calibration certificate should clearly identify the instrument, including a serial number and any model information.
• Environmental conditions in the laboratory environment – At a minimum, the temperature and relative humidity that the calibration was performed at should be specified.
• Date of Calibration
• Identification of the calibration method used – They should perform any calibration in accordance with an established and approved procedure.
• Traceability evidence – Traceability is the main purpose of a calibration certificate, and evidence 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 a 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 manufacture’s specifications but may be limited by the capabilities of the calibration lab.
• Accreditation body logo/information – For certificates that a  manufacturer does not issue, a logo, or identifying information from the body who accredited the lab should be present.