Scope of Calibration

The Standard Scope of Calibration for a device is according to industry standard with the relevant national or international standard, the manufacture’s performance test or against the manufacturer’s specification. If the calibration and measurement procedure includes selection of measuring points these shall be documented and agreed with the customer. If you as a customer have specific requirements on the scope of calibration not covered by our standard scope of calibration above a customer specific Scope of Calibration for the device shall be defined and agreed (deviations requested by the customer shall not impact the integrity of the laboratory or the validity of the results).

Device under test

The device under test will be inspected, cleaned, acclimatized, zeroed and reset as appropriate for the device before being calibrated.

Methods

The methods used by the laboratories are calibration and measurement procedures based on standard methods or methods developed or modified by Element Metech.

Standard methods are methods published either in international, regional or national standards, or by international or regional accreditation organizations, or by National Accreditation Bodies (NAB) or reputable technical organizations, or in relevant scientific texts or journals, or as specified by the manufacturer of the equipment.

Accredited Calibration of single quantities or parameters can always be performed according to the Scope of Accreditation of the laboratory.

The scope of accreditation differs between the accredited calibration laboratories, see the ISO/IEC 17025 accreditations on the website at https://elementmetech.com/certifications-and-accreditations/ for details about the scopes of accreditation and the National Accreditation Bodies (NAB) used. Any measuring points not included in the laboratories scope of accreditation may be calibrated but not under the accreditation (the measuring points will be marked in the calibration report as “not included in the accreditation”).

For an Accredited Calibration of a more complex device (with multiple quantities or parameters to be calibrated) the Scope of Accreditation of the laboratory shall include at least the primary quantities and parameters of the device (and the majority of the measuring points for these quantities and parameters shall be included in the accreditation).

The scope of accreditation differs between the accredited calibration laboratories, see the ISO/IEC 17025 accreditations on the website at www.elementmetech.com/certifications-and-accreditations for details about the scopes of accreditation and the National Accreditation Bodies (NAB) used.

Secondary quantities or parameters of the device not included in the laboratories scope of accreditation shall be calibrated but not under the accreditation (they will be marked in the calibration report as “not included in the accreditation”). Functional tests for the device recommended by the manufacturer shall be included in the calibration (they will be marked in the calibration report as “functional tests”).

Measuring equipment

The calibration procedure and measuring equipment shall be selected to provide an uncertainty of measurement of less than a third of the specification, i.e. a Test Uncertainty Ratio (TUR) ≥ 3, and to ensure that the measurements are traceable to the International System of Units (SI), where possible.

The measuring equipment used to calibrate the device under test will be stated in the calibration certificate.
In the rare cases where the Test Uncertainty Ratio (TUR) < 1 the measurement uncertainty cannot be considered suitable for verify the specification and the status of conformity will normally be reported as not evaluated: Not evaluated (NE), the measured point is measured but is not tested for conformity with tolerance / specification.

Functional tests for the device recommended by the manufacturer (that do that not include a traceable measurement of a defined quantity and thus not have any uncertainty of measurement) shall be included in the calibration procedure (they will be marked in the calibration report as “functional tests”).

Measurement uncertainty

The reported expanded measurement uncertainty will be stated as the standard measurement uncertainty multiplied by the coverage factor k such that the coverage probability corresponds to approximately 95 %. If not otherwise stated the coverage factor is k = 2, which for a normal distribution corresponds to a coverage probability of approximately 95 %, for the reported expanded measurement uncertainty.

The evaluation of measurement uncertainty follows the guidelines in ISO/IEC GUIDE 98 3:2008 Uncertainty of measurement – Part 3: Guide to the expression of uncertainty in measurement (GUM:1995), ILAC P14:09/2020 ILAC Policy for Measurement Uncertainty in Calibration and EA 4/02 M:2022 Evaluation of the Uncertainty of Measurement in calibration. The reported measurement uncertainty applies only to the measured value and do not imply anything regarding the long-term stability of the device under test.

The reported measurement uncertainty applies only to the measured value and do not imply anything regarding the long-term stability of the device under test.

Metrological traceability

The metrological traceability follows the guidelines in ILAC P10:07/2020 ILAC Policy on Metrological Traceability of Measurement Results and ILAC G24:2007 / OIML D 10:2007 Guidelines for the determination of calibration intervals of measuring instruments.

The calibration certificate documents the metrological traceability to national or international standards, which realize the units of measurement according to the International System of Units (SI).

Statement of conformity with tolerance / specification

Any statement of conformity to a specification or standard will be determined in accordance with ILAC publication ILAC G8:09/2019 Guidelines on Decision Rules and Statements of Conformity using the decision rule (4.2.3) with a Non-binary Statement with Guard Band equal to the expanded measurement uncertainty if not otherwise specifically stated or inherent in the specification or standard to be used:

The statement of conformity with tolerance / specification is based on a 95 % coverage probability for the expanded measurement uncertainty and is only valid for the device under test at the tested points.

The statement of conformity with tolerance / specification is reported as:

P Pass – The measured result is within in the acceptance limits
N+ Conditional Pass – The measured result is inside the guard band, i.e. within the tolerance limits but outside the acceptance limits
N- Conditional Fail – The measured result is outside the tolerance limits but with less than the guard band
F Fail – The measured result is outside the tolerance limits with more than the guard band

TL: Tolerance limit / Specification limit (TL_Upper, TL_Lower)
AL: Acceptance limit (AL_Upper = TL_Upper – w, AL_Lower = TL_Lower + w)
w: Guard band equal to expanded uncertainty (w = U)
U: Expanded measurement uncertainty (U)

Other terms that may be used:

NT: Not tested, the measured point is not measured (and not tested for conformity with tolerance / specification)
NS: Not specified, the measured point is measured but has no tolerance / specification limits
NE: Not Evaluated, the measured points are measured but are not tested for conformity with tolerance / specification limits

The status of conformity with tolerance / specification is reported in the result column, which should not be confused with the measurement result given in the measured value and uncertainty columns.

A compilation for all performed tests of the status as received, i.e. before any adjustment/repair, and the status as shipped, i.e. after any adjustment/repair, is reported on the first page:

Device under test specified:

• Pass (P) – All measured results are within the acceptance limits
• Conditional Pass (N+) – One or more measured results are inside the guard band, i.e. within the tolerance limits but outside the acceptance limits
• Conditional Fail (N-) – One or more measured results are outside the tolerance limits but with less than the guard band
• Fail (F) – One or more measured results are outside the tolerance limits with more than the guard band
• Device under test specified but it is not possible to run all tests:
• Not Tested (NT) – One or more measured points are not measured (and not tested for conformity with tolerance / specification)

Device under test not specified:

• Not Specified (NS) – The measured points are measured but have no tolerance / specification limits

Device under test not tested for conformity:

• Not Evaluated (NE) – The measured points are measured but are not tested for conformity with tolerance / specification limits.

The statement of conformity with tolerance / specification is based on the decision rule above and the final judgement, if the device under test is compliant and fit for purpose for its intended use (metrological confirmation), has to be made by the customer.

Electronic calibration documents

Element Metech electronic calibration documents are produced as PDF files and signed digitally. The documents are distributed by Metech Instrument Organizer (MIO™), to registered users or as download links/attachments in delivery notification emails.

You can also get the calibration documents from the Element Metech website via the report number and MIO Id. If your calibration stickers have QR code, the calibration document can be opened directly in a mobile device. Please download the Element Metech electronic calibration documents instruction for more information about digital signatures and how to verify them.

Standard Terms and Conditions

All work and services carried out by Element Metech are subject to, and conducted in accordance with, the Element Metech Standard Terms and Conditions, which are available at www.elementmetech.com/terms or upon request.