G-23 – Recognition of data from specialty gas suppliers and testing laboratories

The copy of this document located on Measurement Canada's website is considered to be the controlled copy.

Category: Gas
Bulletin: G-23
Issue date:
Effective date:


Table of contents


1.0 Purpose

The purpose of this bulletin is to communicate the requirements and conditions that apply to organizations seeking to be recognized by Measurement Canada (MC) to provide test data for natural gas mixtures used in approval evaluations or inspections and calibrations of gas analyzers.

Such data from recognized organizations may be used by MC for the purposes of certifying gas mixtures and generating certificates of calibration accordingly.

2.0 Scope

This bulletin applies to specialty gas suppliers and laboratories seeking to have their data recognized by MC and able to comply with the specific requirements and conditions set forth in this bulletin.

3.0 References

  1. GPA 2172: 1996 – Calculation of Gross Heating Value, Relative Density and compressibility Factor for Natural Gas Mixtures from compositional analysis
  2. GPA 2145: Table for Physical Constants for Hydrocarbons and Other Compounds of Interest to the Natural Gas Industry
  3. GS-ENG-06-12 – Requirements for selection and use of Natural Gas Mixtures used by Measurement Canada
  4. ISO/IEC 17025: 2005 – General Requirements for the Competence of Testing and Calibration Laboratories
  5. ISO 6141: 2000(E) Gas analysis Requirements for certificates for calibration gases and gas mixtures

4.0 Limitations

4.1 This recognition does not delegate legal authority to the operator of the organization to certify gas mixtures intended for use in the verification of meters pursuant to the Electricity and Gas Inspection Act (EGIA).

4.2 For the purposes of satisfying the requirements of the EGIA, the use of data generated by recognized organizations is limited to MC and Authorized Service Providers.

4.3 Recognition of data from a particular organization is limited to the capabilities listed for that particular organization.

5.0 Terminology

Gas analyzer

Any gas analysis device with Measurement Canada approval of type that may be used in a custody transfer application (e.g. gas chromatographers, calorimeters, densitometers, therm-titrators, etc.).

Specialty gas supplier

An organization that prepares gas mixtures or a laboratory that analyzes prepared gas mixtures and that is recognized or seeking to be recognized by Measurement Canada to provide test data.

6.0 Technical conditions and requirements

A specialty gas supplier (referred to hereinafter as organization) that seeks to be recognized by MC to provide test data for gas mixtures, including gas composition and heating value, shall comply with the technical conditions and requirements of this section.

6.1 Gas composition

The supplied gas mixtures shall be in accordance with the requirements stated in GS-ENG-06-12: Requirements for the Selection and Use of Natural Gas Mixtures Used by Measurement Canada.

6.2 Heating value and relative density calculation

The true heating value and relative density of the gas mixtures supplied shall be calculated using the true relative concentrations of all components of the gas mixture, as established in accordance with GPA 2172: Calculation of Gross Heating Value, Relative Density and Compressibility Factor for Natural Gas Mixtures from Compositional Analysis and GPA 2145: Table for Physical Constants for Hydrocarbons and Other Compounds of Interest to the Natural Gas Industry.

6.3 Calibration certificates / test reports produced by the supplier

Subject to section 4.1, the following information shall be included on the calibration certificates / test reports provided by the organization:

  1. Name and address of the organization and the location where the calibrations were carried out, if different from the address of the organization.
  2. Name and address of the supplier, if different from the organization.
  3. Unique identification number of the calibration certificate / test report (such as the serial number).
  4. Calibration and expiry date (maximum of 3 years).
  5. Name, function and signature or equivalent identification of the person(s) authorizing the test.
  6. Authorization date of the calibration certificate / test report.
  7. Page number and total number of pages.
  8. Identification of the method of preparation used.
  9. Identification of the method of analysis used.
  10. Identification of the container (cylinder); lot number, cylinder number, cylinder size.
  11. Name of specified components (nominal value optional).
  12. Gas composition. The reported value of all specified components of the gas mixture must be stated in mole fraction. Balance value is accepted for methane.
  13. Real gas relative density (specific gravity).
  14. Gross heating value for ideal dry gas and real dry gas, expressed in British thermal unit per standard cubic foot (e.g. Btu (60,5)/scf, Btu (IT)/scf, Btu (59)/scf) and/or Joule per standard cubic meter.
  15. Base or standard temperature and pressure used in establishing the heating value.
  16. Compressibility factor (dry gas).
  17. Identification of heating value calculation and method used.
  18. Expanded uncertainty of the content with a coverage factor of two (k=2) /or a statement of compliance with an identified specification or clauses.
  19. Evidence that the measurements are traceable (statement of traceability).
  20. Filling pressure.
  21. Valve outlet connection.
  22. Minimum use pressure (below this pressure significant deviations from stated composition may occur).
  23. Storage and use temperature.

In addition to the above, the following information is recommended to be included on the calibration certificate / test report, when possible:

  1. Name and address of the customer.
  2. Commercial name of the gas mixture.
  3. Equipment used for the preparation.
  4. Equipment used for the analysis.

6.4 Proficiency testing and monitoring of results

6.4.1 In order to assess the proficiency of the organization and to ensure continued compliance with the requirements of this bulletin, the organization shall use methods such as the following:

  1. Participating in inter-comparisons with one or more MC-recognized organizations.
  2. Monitoring the performance of the equipment used and measurement standards using a suitable statistical process control.
  3. Establishing consistency between prepared mixtures and suitable traceable standards.
  4. Using monitoring standards.
  5. Using other methods approved by MC.

6.4.2 The results of these monitoring processes shall be provided to MC upon request.

7.0 Applying for recognition

Organizations seeking to be recognized by MC to provide test data shall supply the following information:

  1. A written expression of interest, including the name and address of the test facility as well as the telephone number and email address of the contact person.
  2. A copy of existing accreditations or certification and reference numbers (e.g. ISO/IEC 17025, ISO 9001), if applicable.
  3. A copy of the scope of the test facility's accreditation, if applicable.
  4. A copy of the last audit report.
  5. A sample of a calibration certificate or test report for the gas mixture.
  6. Information required in subsections 7.1, 7.2, 7.3 and 7.4 of this bulletin.
  7. Any technical information requested by MC's Engineering and Laboratory Services Directorate.

7.1 Traceability

7.1.1 The organization shall submit sufficient information to demonstrate traceability to relevant national standard recognized by MC.

7.1.2 MC's Engineering and Laboratory Services Directorate will perform a technical assessment to determine the organization's ability to provide calibration services within the values claimed in the submission.

7.1.3 The method employed is dependent on the location of the organization on the international traceability chain and current certifications or accreditations.

7.1.4 When traceability to the National Research Council of Canada (NRC) cannot be achieved, the organization shall obtain traceability from a national metrology institute that actively participates in the activities of the Bureau international des poids et mesures (BIPM) either directly or through regional groups that are recognized by MC.

7.1.5 Traceability may also be obtained through a system of calibrated masses and balances that are directly traceable to an NRC or MC-recognized metrology institute.

7.1.6 Traceability to the International System of Units may also be attained by analytical testing through the use of a validated test method and the use of gas standards traceable via certified reference material.

7.1.7 In the case of organizations which have been accredited to ISO 17025 by an institution recognized by the International Laboratory Accreditation Cooperation (ILAC), of which the Standards Council of Canada (SCC) is a signatory member, a certificate of accreditation to ISO/IEC 17025 will be deemed as proof of compliance.

7.2 Measurement uncertainty

7.2.1 The organization shall submit sufficient information on its overall measurement uncertainty and the specific method(s) used in its determination. The uncertainty shall include the contributions from all relevant uncertainty sources. Additional information on the uncertainty evaluation shall be provided as required.

7.2.2 The measurement uncertainty shall be reported at the 95% confidence interval and include all contributors associated with the preparation of the gas mixture and/or heating value determination. When a contributor is not considered, it shall be appropriately noted.

7.2.3 When the preparation and analysis methods are rigorous and valid such as methods published in national, regional or international standards, the organization shall at least identify all uncertainty components and make a reasonable uncertainty estimation based on the measurement and knowledge of the performance of the method.

7.2.4 The method used for uncertainty calculation shall be as prescribed in the ISO Guide for the Expression of Uncertainty (GUM) or ISO 5725 Accuracy (trueness and precision) of measurement methods and results.

7.3 Test equipment

7.3.1 The organization shall submit information related to the test equipment used to obtain test results.

7.3.2 The organization shall demonstrate that the equipment used for preparation and analysis is capable of achieving the accuracy required.

7.4 Technical procedures

The organization shall submit copies of the laboratory procedures used in the preparation of the gas mixture as well as the determination of the heating value. These procedures shall make reference to standard test procedures used (national, regional or international standards).

8.0 Evaluation criteria

MC's evaluation process focuses on the items listed in sections 6 and 7 of this bulletin. It is therefore recommended that the documentation in the submission be organized around these items.

9.0 Recognition

9.1 MC will monitor the performance of recognized organizations and determine whether to continue recognizing the organization based on the results of the review. Recognized organizations will be re-evaluated periodically. MC may perform on-site audits as part of the evaluation and monitoring of recognized laboratories.

9.2 The suitability of MC's recognition process and requirements will be periodically evaluated for effectiveness and may be modified or discontinued as necessary. Recognized organizations must be prepared to update processes and procedures to take into account any changes in MC requirements.

9.3 Requirements may be of a technical or administrative nature. Organizations may, in the future, be required to fulfil certain quality system requirements as MC adjusts its recognition program.

10.0 Recognized organizations

A detailed listing of the organizations recognized by MC and retained by the Engineering and Laboratory Services Directorate, Gas Engineering will be published in the next revision of this bulletin.

11.0 Measurement Canada certification of gas mixtures

11.1 Any request for a gas mixture to be certified by MC shall include the following documentation:

  1. A copy of a completed Calibration Services Request form.
  2. The gas mixture's calibration certificate or test report provided by an organization recognized by MC as meeting the requirements of this bulletin.

11.2 The information shall be sent to the Gas Laboratory Manager, Approval and Calibration Services Laboratory.

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