Calibration Documents

Calibration seal with QR Code

The only way to rely on and retrace test and measurement equipment data, specifications and uncertainties is a calibration report or calibration certificate. Regarding the latter esz offer a unique feature: ISO-compliant and accredited calibration are identical in terms of traceability, accuracy, standards and concerning quality characteristics. There is no difference in procedure or requirements.

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Calibration certificate esz AG

Customers are to decide whether to download a digital copy or to request a common hardcopy. However, esz is concerned about the environment in particular with respect to reports addressing an enormous amount of measurement data to be printed on numerous pages. Thus, a common hardcopy is an abstract listing the most significant facts such as DUT, procedure, standards, conditions, location, measurement uncertainties and a general summary, a pass/fail analysis. The entire report including all measurement data is available online. Customers get to choose from a simple download link or esz AG’s more sophisticated “asset expert”. Additionally, a simple scan (using any mobile scanning device such as a smartphone) of the included QR-code (as part of the calibration seal and calibration report) will lead customers directly to a digital copy of the corresponding calibration report. Take advantage of esz AG’s online archives and help to reduce paper and to protect the environment.

The Calibration Certificate

esz calibration certificates contain basic information such as calibration object and procedure, ambient and measurement conditions, location of calibration and information on uncertainties of measurement as well as other important details:

DIN EN ISO/IEC 17025 compliant: The esz quality management system meets all requirements of DIN EN ISO/IEC 17025:2018. esz calibration certificates are structured and built according to the criteria in section 7.8 of the standard.

Proprietary Calibration Certificate in full DAkkS scope: Regardless of whether we are looking at an ISO / factory calibration or a DAkkS accredited calibration: Calibration procedures, measurement program, quality and extend of service are all treated equally at esz AG. We carry out factory calibrations to the same extent and under the same conditions as accredited calibrations. The services differ only in the cover sheet of the calibration certificate and the accreditation symbol. Further information on this topic can be found here.

Live measurement data of ambient conditions: Instead of fixed intervals of the ambient conditions, esz calibration certificates contain the real-time measurement data of temperature, humidity and air pressure, which were precisely measured during the calibration in the esz laboratory.

Ambient Conditions

Detailed traceability chain: In addition to the accreditation logo, the esz calibration certificate guarantees metrological traceability to the SI unit system or to the underlying metrological references by displaying the uninterrupted traceability chain of the test equipment and calibration devices.

Tracability chain

Graphical representation of measuring data: The measurement steps are represented graphically as line diagrams. This makes it possible to see at a glance whether and how well the tolerances of the device under test are maintained relative to the nominal value.


| 1:Lower specification limit | 2:Intervention/warning threshold | 3:Nominal value | 4:Measured value incl. measurement uncertainty | | 5:Upper specification limit | 6:Standardized tolerance field |

Accurate risk evaluation: Each measurement step is tested for the specific risk of the conformity statement (conformity test). Six cases can occur in the "Remark" column:

  • Pass - without remarks: >95% probability of being within specification (ILAC-G8:09/2019 Fig. 5, Pass)
  • !: Intervention threshold exceeded, >95% probability of being within specification
  • Conditional Pass - ?: with a probability of >50% to 95% of being within the specification, taking into account the measurement uncertainty (MU) (ILAC-G8:09/2019 Fig. 5, Conditional Pass)
  • ?!: over the intervention limit but with a probability of >50 % to 95 % of being within the specification, taking into account the MU
  • Conditional Fail - X?: with a probability of >50% to 95% of being outside the specification, taking into account the MU (ILAC-G8:09/2019 Fig. 5, Conditional Fail)
  • Fail - X: >95 % probability of being outside the specification (ILAC-G8:09/2019 Fig. 5, Fail)

Decision rules for conformity assessment: The so-called "ILAC evaluation" (ILAC = International Laboratory Accreditation Cooperation) is used in esz calibration certificates to determine the decision rules and their measurement step evaluation (in the example in red, not in accordance with the specifications):

ILAC evaluation

  • None: Decision rule according to ILAC evaluation "PASS" but without risk marking, i.e. question marks do not show during calibration and in the calibration certificate.
  • PASS: Standard decision rule according to the QM system of esz AG. Measurement results according to ILAC-G8:09/2019 Fig. 5, Pass and Conditional Pass are assessed as conforming to the specifications. Cases according to ILAC-G8:09/2019 Fig. 5, Conditional Fail and Fail are not considered to comply with the specifications.
  • FAIL: Decision rule according to DIN EN ISO 14253-1:2018-5.2 (on customer request). Measurement results according to ILAC-G8:09/2019 Fig. 5, Pass are assessed as conforming to the specifications. Cases according to ILAC-G8:09/2019 Fig. 5, Conditional Pass, Conditional Fail and Fail are not considered to comply with the specifications.

Extensive reporting: In addition to the conformity statement about accordance with the specifications, esz calibration certificates contain extensive data and terms such as

  • Deviation: Difference between measured value and nominal value
  • Remark: Conformity test per measuring step (ILAC evaluation)
  • Intervention/warning threshold: Set to 80% per default and adaptable to customer requirements
  • Conformity test: Determination of conformity of measurements with specifications (successful conformity tests per measuring step)
  • MU: Measurement uncertainty; estimate for the range in which the calibration value of a measured quantity lies, determined according to EA 4/02
  • Specification: Definition of the accepted properties of a device by the user:

– %rdg: Percent of measured value (reading = display) – D: Digit (display’s least significant digit) – FS: Full Scale – ppm: parts per million (10-6) – ppb: parts per billion (10-9) – rdg: reading

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The Calibration Seal


Safety and trust are invisible. esz AG’s calibration seal facilitates users to display safety and trust to the naked eye. The calibration seal contains a unique number, date, due date and a QR-code. The QR-code enables users and auditors to speed up the process of obtaining and verifying measurement data. QR-codes can be interpreted and processed using a dedicated app on a mobile imaging device such as a camera phone, smartphone or tablet PC. Users will instantly be linked to an external URL containing the corresponding calibration report. The digital copy of a calibration report is displayed providing no means to alter any of the original test and measurement equipment data. The QR-code consists of a 128-Bit encrypted GUID (Global Unique Identifier) featuring more than 3,4 · 1038 possible combinations (in Germany the possibility to get struck by lightning is approximately 3,4 · 107), needless to point out and stress the advantage over common numbering and identification systems. As opposed to customary identification methods the QR Code enables users to only read a calibration report rather than providing means to access and alter owner specific data. The QR Code offers high encryption in terms of data security alongside high-speed data accessibility and availability.

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