S-G-03–Specifications for the approval of type of gas meters, ancillary devices and associated measuring instruments

Category: Gas
Issue date:
Effective date:
Revision number: 1
Supersedes: LMB-EG-08 and S-G-03


Part 1: General

Table of contents


1.0 Purpose

The purpose of these specifications is to establish the metrological, technical, marking, sealing/security, administrative and performance test requirements for the approval of gas meters, ancillary devices and associated measuring instruments based on any measurement technology or principle that is used to measure the quantity or properties of gas at operating conditions.

All metering features or functions of devices that are not explicitly addressed in these specifications are also subject to any additional Measurement Canada (MC) requirement and specification that is applicable based on the technology, principle, feature or function.

These specifications address general requirements in Part 1 and additional requirements applicable to various types of devices are set forth in subsequent parts specific thereto.

This document also provides the tests that MC or an MC-recognized test facility will carry out as well as the test conditions. Where an MC-recognized test facility carries out the testsFootnote 1-1, applicants shall submit test results with the application for approval, as prescribed in Part III, paragraph 13(c) of the Electricity and Gas Inspection Regulations (EGIR).

2.0 Scope

These specifications apply to gas meters, ancillary devices and associated measuring instruments approved by MC pursuant to the requirements of the Electricity and Gas Inspection Act (EGIA) and the EGIR.

Integral correction devices and devices for internal temperature compensation are included in the scope of these specifications as well as any other electronic devices that may be attached to the gas meter.

These specifications shall not be applied to liquefied gas or steam meters.

3.0 Authority

These specifications are issued under the authority of section 9 of the EGIA and Part III of the EGIR established thereto.

4.0 References

Where conflict exists between these specifications and the following reference documents, these specifications take precedence.

5.0 Definitions

Ancillary (auxiliary) device (OIML R137-1, 3.1.8) (dispositif complémentaire (appareil auxiliaire))

Device intended to perform a particular function, directly involved in elaborating, transmitting or displaying measurement results. An ancillary device is not necessarily subject to metrological control and may be integrated in the gas meter.

Associated measuring instrument (OIML V1, 5.09) (instrument de mesure associé)

Instrument for the measurement of a quantity, other than the measurand, the value of which is used to correct or convert a measurement result. Typically, an associated measuring instrument is connected to a device (correction device, conversion device, calculatorFootnote 1-2) that is part of a measuring instrument and that changes (corrects, converts) the measurement result to obtain a value for the measurand under specified conditions.

Attestation of compliance (attestation de conformité)

Attestation originating from an authorized signing authority who has been appropriately designated by the measuring instrument manufacturing corporation to represent it for these purposes as part of the pattern approval process.

Base conditions (OIML R137-1, 3.2.19) (conditions de base)

Conditions to which the measured volume of gas is converted (examples: base temperature and base pressure).

Contractor's badge (plaque du fournisseur)

Nameplate, tag, sticker, electronic display or other suitable means permanently affixed to a measuring instrument in a conspicuous location. The badge may be used to display or provide access to the instrument's inspection number assigned by the contractor and other information relative to the current mode of operation of the instrument to which the badge is attached.

Correction (VIM 2.53)

Compensation for an estimated systematic effect. The compensation can take different forms, such as an addend or a factor, or can be deduced from a table.

Correction device (OIML R137-1, 3.1.7) (dispositif de correction)

Device intended for correction of known errors as a function of e.g. flow rate, Reynolds number (curve linearization), or density, pressure and/or temperature.

Conversion

Conversion of the measurement at operating conditions into measurement at base or standard conditions by taking into account the gas characteristics (i.e. pressure, temperature, composition, density).

Conversion device (dispositif de conversion)

Integral or non-integral device or function which automatically converts the volume or mass measured at operating conditions into a volume at base or standard conditions by taking into account the flowing gas conditions and characteristics.

Cyclic volume (OIML R137-1, 3.2.3) (volume cyclique)

Volume of gas corresponding to one full revolution of the moving part(s) inside the meter (working cycle). The cyclic volume is only applicable to positive displacement gas flow meters.

Durability (OIML R137-1, 3.2.10) (durabilité)

Ability of a measuring instrument to maintain its performance characteristics over a period of use.

Electronic display (affichage électronique)

Device or other means used to visually present the value of a measured quantity and other relevant information. It may take the form of an integral part of a measuring instrument (e.g. gas meter) or a separate display module.

Electronic register (registre électronique)

Memory location integral or non-integral to the measuring instrument where the value of a measured quantity is electronically recorded.

Fault (OIML R137-1, 3.2.7) (défaut)

Difference between the error of indication and the error determined under reference conditions of a meter.

Flow computer (débitmètre-ordinateur)

Device that receives and transforms the output signals from one or more flow measuring devices or from another flow computer and possibly from the associated measuring instruments, and, if appropriate, stores data in memory until they are used. In addition, the flow computer may be capable of transmitting and receiving data from peripheral equipment.

Flow rate, Q (OIML R137-1, 3.3.1) (débit)

Quotient of the actual quantity of gas passing through the gas meter and the time taken for this quantity to pass through the gas meter.

Flow algorithm (algorithme d'écoulement)

Mathematical relationship used to transform the measured pressure differential in the measuring instrument to a mass flow or volumetric flow rate at operating conditions.

Gas meter (OIML R137-1, 3.1.1) (compteur de gaz)

Instrument intended to measure, memorize and display the quantity of gas passing the flow sensor.

Host meter (compteur hôte)

Gas meter to which ancillary devices or indicating device have been attached.

Indicating device (OIML V1, 5.04) (dispositif indicateur)

Part of the measuring instrument which displays the measurement results either continuously or on demand.

Influence quantity (VIM 2.52) (grandeur d'influence)

Quantity that, in a direct measurement, does not affect the quantity that is actually measured, but affects the relation between the indication and the measurement result.

Integral element (élément intégré)

Being part of a particular approved measuring instrument (e.g. integral volume conversion function, integral pulse initiator, integral indicating device).

Intrinsic error (OIML D 11, 3.7) (erreur intrinsèque)

Error determined under reference conditions.

Linearity (linéarité)

Maximum difference between the weighted mean error and any of the individual errors for test points between Qmin and Qmax.

Maximum flow rate, Qmax (OIML R137-1, 3.3.2) (débit maximal)

Highest flow rate at which a gas meter is required to operate within the limits of its maximum permissible error, whilst operated within its rated operating conditions.

Maximum peak-to-peak error (erreur maximale crête à crête)

Difference between the largest and the smallest errors throughout the calibrated range of the meter.

Maximum permissible error (VIM 4.26) (erreur maximale tolérée)

The maximum permissible error is the extreme value of measurement error, with respect to a known reference quantity value, permitted by specifications or regulations for a given measurement, measuring instrument, or measuring system.

Maximum permissible meter / meter tube step change (variation d'échelon maximale permise du compteur ou de sa conduit)

Largest allowable diameter ratio between the inside diameter of the meter tube (upstream and downstream section) and the inside diameter of the meter. It is provided by the meter manufacturer.

Maximum permissible meter non-axial alignment (écart d'alignement non-axial maximal permis du compteur)

Largest allowable angle of the meter alignment with the pipe centerline. It is provided by the meter manufacturer. Small variations in cone alignments have a significant effect on the performance of cone-shaped differential pressure meters.

Maximum working pressure, Pmax (OIML R137-1, 3.3.9) (pression de travail maximale)

Maximum internal pressure that a gas meter can withstand, within its rated operating conditions, without deterioration of its metrological performance.

Measurand (OIML R137-1, 3.1.2) (mesurande)

Quantity intended to be measured.

Measuring instrument (instrument de mesure)

A gas meter, ancillary device or associated measuring instrument used for the purpose of making measurements of, or obtaining the basis of a charge for, gas supplied to a purchaser. The term measuring instrument is equivalent to the term meter in the Electricity and Gas Inspection Act and Electricity and Gas Inspection Regulations.

Measuring transducer (VIM 3.7) (transducteur de mesure)

Device, used in measurement, that provides an output quantity having a specified relation to the input quantity. Examples: Thermocouple, electric current transformer, strain gauge, pH electrode, Bourdon tube, bimetallic strip.

Mechanical indicating device (dispositif indicateur mécanique)

Pointer-type or drum-type mechanical device that is integral or non-integral to the gas meter, where the value of a measured quantity is recorded and visually presented.

Minimum flow rate, Qmin (OIML R137-1, 3.3.3) (débit minimal)

Lowest flow rate at which a gas meter is required to operate within the limits of its maximum permissible error, whilst operated within its rated operating conditions.

Minimum measured quantity (quantité minimale mesurée)

Smallest quantity for which the measurement is metrologically acceptable for a measuring instrument. It is declared/attested by the manufacturer.

Minimum working pressure, Pmin (OIML R137-1, 3.3.9) (pression de travail minimale)

Minimum internal pressure that a gas meter can withstand, within its rated operating conditions, without deterioration of its metrological performance.

Module (module)

Self-contained component of a measuring instrument that has a well-defined interface to the other components of the measuring instrument. It often has its own Notice of Approval and is interchangeable.

Non-integral element (élément externe)

Used with but not part of a particular approved measuring instrument and separately approved (e.g. non-integral pressure/temperature transducers/transmitters, non-integral pulse generators).

Non-volatile memory (mémoire rémanente)

Memory that retains data even if the power supply is turned off.

Notice of approval (avis d'approbation)

Legal confirmation that a measuring instrument meets applicable regulatory requirements and can be used for trade measurement in Canada.

Operating conditions (OIML R137-1, 3.12.16) (conditions de fonctionnement)

Conditions of the gas (temperature, pressure and gas composition) at which the quantity of gas is measured.

Quantity of gas (OIML R137-1, 3.2.1) (quantité de gaz)

Total quantity of gas obtained by integrating the flow passed through the gas meter over time, which is expressed as volume (V) or mass (m), disregarding the time taken.

Rated capacity (capacité nominale)

Qmax determined by the manufacturer.

Rated operating conditions (OIML R137-1, 3.2.17) (conditions assignées de fonctionnement)

Conditions of use giving the range of values of the measurand and the influence quantities, for which the errors of the gas meter are required to be within the limits of the maximum permissible error.

Reference conditions (OIML R137-1, 3.2.18) (conditions de référence)

Set of reference values, or reference ranges of influence quantities, prescribed for testing the performance of a gas meter, or for the intercomparison of the results of measurements.

Registration (enregistrement)

Visual indication and recorded representation of quantity.

Relative error (erreur relative)

Absolute error of measurement divided by the conventional true value of the measurand, and traditionally referred to as the true error. Expressed as a percentage, relative error is calculated as follows:

(E r) = (((Q m) – (Q s)) ÷ (Q s)) × 100% = (((Q m) ÷ (Q s)) – 1) × 100%

Where,

  • Er is the relative error of the meter under test, expressed in percent (%)
  • Qm is the quantity indicated by the device under test
  • Qs is the quantity indicated by the reference standard, expressed in the same units as Qm
Repeatability error (erreur de répétabilité)

Difference between the largest and the smallest results of successive measurements of the same quantity carried out under the same conditions.

Retrofit (rattrapage)

Addition of a component or an accessory to an existing measuring instrument that was approved and manufactured without it.

Reynolds number (nombres de Reynolds)

Dimensionless ratio which can be expressed in terms of the volumetric flow rate (Q), the inside pipe diameter (D), the flowing gas density (ρ) and the flowing gas absolute viscosity (µ).

Sensor (VIM 3.8) (capteur)

Element of a measuring system that is directly affected by a phenomenon, body, or substance carrying a quantity to be measured. Examples: Sensing coil of a platinum resistance thermometer, rotor of a turbine flow meter and Bourdon tube of a pressure gauge.

Supercompressibility (surcompressibilité)

Within the range of conditions normally encountered in the natural gas industry, the deviation of the actual density and the ideal gas density obtained by the ideal gas law (Charles & Boyles). Calculation of supercompressibility factor is in accordance with AGA Report No.8: Compressibility and Supercompressibility for Natural Gas and Other Hydrocarbon Gases – American Petroleum Institute MPMS Chapter 14.2 (Second Edition, 1994).

Telemetering (télémesure)

The transmission of measurement information with the aid of intermediate meansFootnote 1-3 that permits the source meter's register reading to be duplicated and/or interpreted at a distance.

Telemetering device (dispositif de télémesure)

Device used in a telemetering system to duplicate the register reading of the source meter. The device may be external or integral to the source meter.

Telemetering system (système de télémesure)

All devices and equipment used to duplicate and/or interpret a source meter's register reading(s) at a distance.

Test limit (limite d'essai)

Limit established when the specification limit is adjusted for the associated measurement uncertainty.

Transitional flow rate, Qt (OIML R137-1, 3.3.4) (débit de transition)

Flow rate which occurs between the maximum flow rate Qmax and the minimum flow rate Qmin that divides the flow rate range into two zones, the "upper zone" and the "lower zone", each characterized by its own maximum permissible error.Footnote 1-4

Transmitter (transmetteur)

Device that contains a measuring transducer and amplifies and/or converts the transducer's raw electrical signal to another signal type for transmission over longer distances.

Uncertainty (VIM 2.26) (incertitude de mesure)

Non-negative parameter characterizing the dispersion of the quantity values being attributed to a measurand, based on the information used.

Weighted mean error (erreur moyenne pondérée)

The weighted mean error is defined as:

Weighted mean error = ((K1 × E1) + (K2 × E2) + … + (Kn × En)) ÷ (K1 + K2 + … + Kn)

With

(K i) = (Q i) ÷ (Q max)

For Qi ≤ 0.7 Qmax

(K i) = 1.4 - ((Q i) ÷ (Q max))

For 0.7 Qmax < QiQmax

Where,

  • Qi is the test flow rate.
  • ki is the weighting factor at the flow rate Qi.
  • Ei is the error at the flow rate Qi.

6.0 Units

Except where otherwise stated in these specifications, the following shall apply.

6.1 Use of units

6.1.1 A measuring instrument shall not provide an indication or record, or be marked in a mixture of the International System of Units (SI) and the imperial system.

6.1.1.1 The requirement specified in 6.1.1 shall not be applied to electronic devices capable of performing calculations necessary to convert from the imperial system to the SI, or vice versa.

6.1.2 Measuring instruments which provide for the selection of SI units or imperial units shall have a provision for identifying the units the instrument is set up to measure.

6.2 Metric units of measure

6.2.1 Metric units of measure shall be expressed in the SI units of measure listed in the Canadian Standards Association's (CSA) Metric Practice Guide Z234.1.

6.2.2 Where a conflict exists between the CSA standard Z234.1 and the EGIA or the EGIR, the legislative requirements shall apply.

6.3 Electronic display of units of measure for non-trade purposes

The display of units of measure for non-trade purposes, such as monitoring, is permitted.

7.0 Metrological requirements

Except where otherwise stated in these specifications, the following requirements shall apply.

7.1 Rated operating conditions

  1. Ambient temperature range
    1. Non-temperature-controlled environment
      In the case of measuring instruments intended for operation in a non-temperature-controlled environment, the ambient temperature range shall be at least −30 °C to 40 °C.
    2. Temperature-controlled environment
      In the case of measuring instruments intended for operation in a temperature-controlled environment, the ambient temperature range shall be as specified by the applicant and such restrictions shall be set out in the Notice of Approval (NOA) issued by MC.
  2. Ambient relative humidity
    As specified by the applicant and at least up to 93% (non-condensing).
  3. Atmospheric pressure
    As specified by the applicant and shall cover at least 86 kPa to 106 kPa (absolute).
  4. DC mains voltage
    As specified by the applicant.
  5. AC mains voltage
    V~nom - 15% to V~nom + 10%
  6. AC mains frequency
    ƒnom – 2% to ƒnom + 2%
  7. Operating flow rate range
    Qmin to Qmax inclusive.
  8. Type of gases
    As specified by the applicant.
  9. Working pressure range
    Pmin to Pmax inclusive.

7.2 Gas meter flow rate characteristics

7.2.1 The flow rate characteristics of a gas meter based on measurement technology sensitive to flow rate changes and/or changes in flow profile (e.g. laminar to turbulent) shall be defined by the values of Qmin, Qt and Qmax.

7.2.2 Unless otherwise specified by MC, the ratios and relations shall be within the following ranges:

  1. Where Qmax / Qmin is ≥ 50 → Qmax / Qt shall be ≥ 10
  2. Where Qmax / Qmin ≥ 5 and < 50 → Qmax / Qt shall be ≥ 5

7.3 Maximum permissible errors

7.3.1 General

7.3.1.1 A measuring instrument shall be designed and manufactured such that its errors do not exceed the applicable maximum permissible error (MPE) under rated operating conditions as specified in subsection 7.1.

7.3.1.2 The applicable MPE to various gas meter applications, ancillary devices and associated measuring instruments are set forth in subsequent parts specific thereto. (See Appendix A)

7.3.2 Correction for known errors

A measuring instrument may be equipped with a correction device/function intended to reduce the errors as close as possible to the zero value. Subject to subsection 7.3.2.1, such a correction device shall not be used for the correction of a pre-estimated drift.

7.3.2.1 Predetermined error relationships

Unless permitted by the NOA, a measuring instrument shall not be equipped with a correction device/function which extrapolates a meter's performance through characterization of a general meter type at or below Qmin.

7.4 Linearity

The linearity of error shall be within ± 0.4%, except where otherwise stated in these specifications. (See Appendix A)

7.5 Repeatability

The repeatability of the errors of at least three consecutive measurements at the specific flow rate shall be less than or equal to one third of the MPE as specified in 7.3.1.2, except where otherwise stated in these specifications. (See Appendix A)

7.6 Working pressure

The requirements as specified in subsection 7.3 shall be fulfilled over the whole working pressure range.

7.7 Temperature

The requirements as specified in subsection 7.3 shall be fulfilled over the whole temperature range.

7.8 Durability

Subject to subsection 12.5.8, the fault of a gas meter for flow rates from Qt up to Qmax shall be less than or equal to half the MPE.

7.9 Vibrations and shocks

7.9.1 A gas flow meter shall withstand vibrations and shocks with the following specifications:

  1. Vibrations:
    1. Total frequency range: 10 Hz – 150 Hz
    2. Total root mean square (RMS) level: 7 m-s-2
    3. Acceleration spectral density (ASD) level 10 Hz – 20 Hz: 1 m²s-3
    4. ASD level 20 Hz – 150 Hz: −3 dB/octave
  2. Shocks: height of fall: 50 mm

7.9.2 The fault after the application of vibrations and shocks shall be less than or equal to half the MPE over the whole flow rate range.

7.10 Orientation

7.10.1 Subject to 7.10.2, the measuring instrument shall fulfill the metrological requirements specified in subsections 7.3 and 7.4 for all orientations.

7.10.2 Where the measuring instrument operates correctly while installed in certain orientations recommended by the manufacturer and for which approval is sought, the metrological requirements mentioned in subsections 7.3 and 7.4 shall be fulfilled for these orientations only.

7.11 Flow direction

If the gas meter is marked as being able to measure the flow in both directions, the requirements mentioned in subsections 7.3 and 7.4 shall be fulfilled for each direction separately.

7.12 Flow disturbance

7.12.1 Subject to 7.12.2, for types of gas meters whose accuracy is affected by flow disturbances, the shift of the error due to these disturbances shall not exceed one third of the MPE.

7.12.2 Where a gas meter is specified to be installed in a specific piping configuration producing only mild flow disturbances, such restrictions shall be set out in the NOA issued by MC and the gas meter shall only be installed in the specific piping configurations in which its accuracy has proven to stay within the requirement.

7.13 Drive shaft (torque)

For types of gas meters provided with one or more drive shafts, the manufacturer shall provide the maximum torque that can be applied without exceeding one third of the MPE.

7.14 Different gases

The types of gas meters which are intended to be used for different gases shall comply with the requirements specified in subsection 7.3 over the whole range of gases for which they are specified by the manufacturer.

7.15 Influences from ancillary devices

Gas meters provided with ancillary devices shall be designed such that none of the functions of the ancillary devices (e.g. provisions for communication purposes) affect the metrological behaviour.

7.16 Supply voltage variation

7.16.1 When a supply voltage variation occurs, the error of the measuring instrument requiring a power supply from the mains shall not:

  1. exceed the MPE;
  2. deviate by more than ±0.2% from the errors at nominal supply voltage.

7.17 Uncertainty

7.17.1 The estimation of the expanded uncertainty U shall be made in accordance with the Guide to the expression of uncertainty in measurement (GUM) with a level of confidence of approximately 95%.

7.17.2 Subject to 7.17.3, the expanded uncertainty U of determination of errors of the measured gas quantity shall be less than one fifth of the applicable MPE, as specified in subsection 7.3, where applicable.

7.17.3 Where the expanded uncertainty U of errors exceeds one fifth of the applied MPE, the test results shall be approved by reducing the applied MPE with the excess of the uncertainties.

New maximum permissible error = ± ((6 ÷ 5) × MPE – (1.645×u))

8.0 Technical requirements

Except where otherwise stated in these specifications, the following requirements shall apply according to the measuring instrument technology, principle, feature or function.

8.1 Design, composition and construction

8.1.1 The design shall be suitable for the intended purpose and expected service conditions.

8.1.2 The construction shall be mechanically and electrically sound, and the materials (e.g. finish) shall be such as to provide assurance of long life and sustained accuracy.

8.1.3 Provisions incorporated in gas meters for sensing flowing gas temperature and the performance of temperature conversion and/or supercompressibility correction shall meet the applicable performance requirements over a minimum temperature range of 40 °C.

8.1.4 Subject to 8.1.4.1, in situations in which the automatic conversion of metered volume takes place, the registration of the unconverted and the converted volume shall be provided at least by the measuring instrument with integral volume conversion functions or by the non-integral volume conversion device.

8.1.4.1 Where the measuring instrument is not able to provide the registration of the unconverted and the converted volume, the NOA shall specify that the measuring instrument shall be used in conjunction with an associated device which can provide the specified information.

8.2 Case

8.2.1 The case of a measuring instrument intended to contain gas shall be so designed and constructed to effectively maintain its accuracy over the entire ranges of its operating parameters.

8.2.2 The case of a measuring instrument shall be designed and constructed to withstand environmental conditions and prevent any exterior foreign substance from entering the measuring instrument.

8.3 Zero flow

The gas meter totalization shall not change when the flow rate is zero and the installation conditions are free from flow pulsations.Footnote 1-5

8.4 Flow direction

8.4.1 Measurement of bidirectional flow

8.4.1.1 Where measuring instruments are designed for bidirectional gas flow, the quantity of gas passed during reverse flow shall be recorded separately.

8.4.1.2 The MPE as specified in subsection 7.3 shall be met for both forward and reverse flow.

8.4.2 Reverse flow

Gas meters designed for unidirectional measurement shall either prevent reverse flow, or shall withstand incidental or accidental reverse flow without deterioration or change in their metrological properties concerning forward flow measurements.

8.5 Indication provisions

8.5.1 Subject to 8.5.2, every measuring instrument whose function is to provide measured quantity in corresponding units shall be equipped with an integral indicating device or provide for connection or attachment of a non-integral indicating device.

8.5.2 Where a measuring instrument is approved for use with an approved non-integral indicating device, it shall have an approved compatible indicating device connected to it in a manner which allows users to access the measured quantities in corresponding units where they are obtained via radio frequency transmitters, the communication port or other form of electronic data communication, subject to the following conditions:

  1. The indicator shall be capable of displaying each legal unit of measure for which the measuring instrument is approved;
  2. Where an electronic device is used to obtain the units of measure, the software/firmware used to obtain the measurement readings shall be approved.Footnote 1-6

8.6 Output

8.6.1The capacity per measuring instrument rotating mechanical output shaft (instrument drive or wriggler) shall be such that at Qmax, the output shaft makes at least one rotation every two minutes.

8.6.2 Where the measuring instrument output is in a form of digital communication, the poling frequency shall be such that the time required verifying the MPE is no more than two minutes.

8.7 Power sources

8.7.1 Measuring instrument may be powered by three types of power sources that may be used alone or in combination:

  1. Mains power sources
  2. Non-replaceable power sources
    The indicated lifetime of the power source shall guarantee that the measuring instrument functions correctly for at least as long as the operational lifetime of the measuring instrument as stated by the manufacturer.
  3. Replaceable power sourcesFootnote 1-7
    The replacement of the power source shall not adversely affect the programming, metering information or subsequent operation of the measuring instrument.

8.7.2 Electronic devices which calculate measurement units shall be designed such that in the event of a power failure, the measured or calculated quantity of gas as well as any configuration parameters, constants and calibration parameters obtained just before the failure are not lost (i.e. non-volatile memory).

8.8 Software

The software requirements applicable to measuring instruments within the scope of these specifications are established by the following MC specifications:

  1. S-EG-05—Specifications for the Approval of Software Controlled Electricity and Gas Metering Devices
  2. S-EG-06—Specifications Relating to Event Loggers for Electricity and Gas Metering Devices

9.0 Marking requirements

Except where otherwise stated in these specifications, the following requirements shall apply according to the measuring instrument technology, principle, feature or function.

9.1 General

9.1.1 All required markings shall be easily legible and indelible under rated operating conditions and shall not be adversely affected by environmental conditions.

9.1.2 Markings shall not lead to confusion.

9.1.3 As relevant, the following information shall be marked on the casing or on a nameplate permanently affixed to the measuring instrument in such a way as to be easily readable when installed:

  1. Departmental approval number;
  2. Manufacturer's name or registered trademark;
  3. Model or type designation;
  4. Serial number;
  5. Ambient temperature range, where less than −30 °C to 40 °C;
  6. Maximum allowable operating pressure and where applicable, minimum operating pressure;
  7. Maximum flow rate Qmax=…<unit>;
  8. Minimum flow rate Qmin =…<unit>;
  9. Transitional flow rate Qt=…<unit>;Footnote 1-8
  10. Gas temperature and pressure range for which the errors of the measuring instrument shall be within the limits of the MPE;Footnote 1-8
  11. Pulse values of frequency outputs;Footnote 1-8
  12. Type and range for analogue input and/or output signal;Footnote 1-8
  13. Protocol/interface for digital input and/or output.Footnote 1-8

9.1.4 Bar codes or QR (Quick Response) codes shall only be used to supplement or duplicate information that is already marked on the measuring instrument's nameplate or displayable on the instrument's electronic display as well as an external device (by remote interrogation software).

9.2 Temperature converted volume

Integral temperature converting meters and non-integral temperature converting modules shall have the temperature to which the registered volume is converted (e.g. 15 °C or 60 °F) permanently and prominently marked on nameplates irrespective of background colour.Footnote 1-8

9.3 Pressure converted volume

9.3.1 Integral pressure converting meters and non-integral pressure converting modules shall have the following additional information marked on the nameplateFootnote 1-8:

  1. Instrument's pressure transducer range;
  2. Base pressure;
  3. Where a gauge pressure sensor is used, the atmospheric pressure, or range of atmospheric pressures, for which the instrument is suitable.

9.4 Unidirectional gas flow

Gas meters designed for only unidirectional measurement shall be marked showing the direction of gas flow or shall have the inlet connection identified.

9.5 Bidirectional gas flow

9.5.1 Gas meters designed to measure bidirectional gas flow shall be marked with a double-headed arrow, with a plus (+) and minus (-) sign to indicate which flow direction is positive and which flow direction is negative, respectively.

9.5.2 Electronic devices designed to measure bidirectional gas flow shall provide for and permit access to the identification of the direction of the flowing gas via the device's electronic display or output to an external device (by remote interrogation software) in a clear and unambiguous manner.

9.6 Output shaft

Measuring instruments equipped with an external output shaft shall have their direction of rotation visibly marked in the vicinity of the shaft together with the capacity per revolution of the shaft when a device or a cover is attached.

9.7 Electronic devices

9.7.1 Measuring instruments requiring an external power supply for operation shall have the following information marked on the nameplate:

  1. The nominal voltage;
  2. The nominal frequency.

9.7.2 Measuring instruments powered by a battery or other power sources which must periodically be replaced shall meet the following requirements:

  1. The remaining battery capacity shall be indicated in units of time;Footnote 1-8 or
  2. an automatic alarm shall be incorporated that provides an indication when battery life is below 10%.

9.7.3 For a non-replaceable power source, the operational lifetime of the measuring instrument or, alternatively, the remaining battery capacity in units of time shall be indicated.Footnote 1-8

9.8 Software

The meter/component firmware and/or software version(s) shall be prominently indicated.Footnote 1-8

9.9 Connection terminals

The connection terminals shall be identified by markings on the measuring instrument or by a table or a schematic diagram permanently affixed to the measuring instrument. Where a measuring instrument is designed to accept a non-interchangeable cable connector, the connection terminal for that connector shall be exempted from this requirement.

9.10 Contractor

9.10.1 Where the information required on a contractor's badge is displayed on a nameplate, space shall be provided for the attachment of the contractor's badge.

9.10.2 Where an alternate method is used to display the information required on a contractor's badge, it shall be such that the information is readily accessible at the metering location.

9.11 Operating information

Where a measuring instrument is provided with an adjustment allowing the user to change any operating parameters (e.g. base pressure, base temperature, etc.) or its ranges may be set by the user, the manufacturer shall provide a nameplate, tag, sticker, electronic read or read/write system (with security) or other suitable means for marking the applicable information.

9.12 Ancillary devices

9.12.1 If an ancillary device is not subject to legal metrology control, this shall be clearly indicated.

9.12.2 Ancillary devices integral to a gas meter shall have a unique identifier (i.e. serial number) marked on the visible face of the device when mounted in the gas meter.

9.12.3 Where the ancillary device equipped with an external input is attached to the output shaft of a measuring instrument, the following shall be visibly marked in the vicinity of the input shaft:

  1. The direction of rotation;
  2. The capacity per revolution.Footnote 1-9

10.0 Sealing requirements

Except where otherwise stated in these specifications, the following shall apply.

10.1 Every measuring instrument and any interchangeable measuring component thereof shall be constructed so that access to the working parts, adjustments and programming may be effectively prevented by use of the conventional sealing method as per S-EG-02—Specifications for Approval of Physical Sealing Provisions for Electricity and Gas Meters.

10.2 Electrically operated measuring instruments shall have sealing provisions designed to accommodate the conventional sealing method, as per S-EG-02, to prevent unauthorized access to fuses, circuit breakers, signal connections and the primary and backup electrical source.

10.3 Gas meters of modular design which allow interchangeability of modules shall have suitable provisions for sealing:

  1. each module separately;
  2. modules together.

10.4 The exposed ends of the drive shaft shall be suitably protected when a gas meter is not connected to an attachable ancillary device.

10.5 Subject to 8.5.1, means provided for the registration of cumulative volume, mass or energy units shall be non-resettable under normal operating conditions once the measuring instrument is sealed.

11.0 Administrative requirements

Except where otherwise stated in these specifications, the following shall apply.

11.1 Application for approval

11.1.1 An applicant shall follow the MC application process when applying for an NOA under section 9 of the EGIA.

11.1.1.1 Where applicable, the applicant shall provide MC with the gas meter cyclic volume.

11.1.2 In addition, if software is employed, the following shall be included:

  1. The type approval documentation prescribed by S-EG-05—Specifications for the Approval of Software Controlled Electricity and Gas Metering Devices;
  2. A description of how the device equipped with an event logger meets the requirements prescribed by S-EG-06—Specifications Relating to Event Loggers for Electricity and Gas Metering Devices.

11.2 Approval evaluation

11.2.1 Gas meters, ancillary devices and associated measuring instruments shall conform to the approved type and the documentation that was submitted in support of approval obtainment.

11.2.2 Compliance with the requirements of these specifications shall be established on the basis of a combination of performance testing and written attestations of compliance, where applicable and when accepted by MC.

11.2.2.1 An attestation of compliance shall:

  1. contain the company letterhead;
  2. be addressed to MC;
  3. refer to the approval project and approval number (where applicable);
  4. indicate the section(s) of the specifications that the applicant is attesting to;
  5. explain how the requirements are met.

11.2.3 All attestations of compliance and testing data shall serve as records of compliance and shall be maintained as permanent records in a device's type approval file.

11.2.4 Telemetering devices/functions and ancillary devices incorporated within a gas meter submitted for approval by MC shall be evaluated and approved as integral components of the gas meter and included in its NOA.

11.2.5 Retrofit-type separate ancillary and telemetering devices subject to approval by MC shall be evaluated and approved as separate devices and issued their own NOA.

11.2.6 Retrofit-type telemetering devices submitted for approval shall be evaluated to ensure they do not impair or impact the operation of the approved source gas meter makes/models intended to be retrofitted.

11.2.6.1 Manufacturers of retrofit-type telemetering devices shall demonstrate to MC that the use of their devices is authorized by the manufacturer of the approved source gas meter makes/models intended to be retrofitted.

11.3 Samples

Except where otherwise requested by MC, the following rules shall apply:

  1. Where a measuring instrument comes in various sizes and the design, composition and construction are proportional to its size and the pattern remains the same for the series, two samples representing the smallest and the largest size in the series shall be submitted for evaluation.
  2. Where a measuring instrument comes in three sequential nominal sizes, the middle nominal sized device shall be evaluated.
  3. Where a homogeneous series extends to device sizes that exceed the laboratory's capacity, the next nominal size smaller than the largest size in the series shall be evaluated.

11.4 Provisions for Measurement Canada testing

When testing is performed by MC, the following shall be supplied or made available by the applicant:

  1. Subject to subsection 11.3, the number of sample measuring instruments manufactured in conformity with the type;
  2. Any special equipment required to evaluate the measuring instrument;
  3. A person with a thorough knowledge of the measuring instrument;
  4. Other assistance as may be determined throughout the approval process.

11.5 Provisions for third party test data from a recognized test facility

11.5.1 Where the applicant submits test results from a test facility recognized by MC, the test plan shall be approved by MC prior to the testing.

11.5.2 Where test conditions established in these Specifications are not within the scope of recognized test facilities, a proposed method for maintaining the required test conditions during the applicable testing for evaluation shall be submitted to MC and include:

  1. a clear description of the method used to establish and maintain the required test condition(s);
  2. quality assurance and quality control processes used to establish and maintain the required test condition(s).

11.5.3 Where test facilities are not available to perform tests over the entire operating pressure range of the gas meter, the applicant shall provide test data demonstrating that the pattern to which the gas meter belongs is either insensitive to the operating pressure or may be predicted using a dimensionless number such as the Reynolds number. This will not cause the gas meter's accuracy to exceed the MPE specified in subsection 7.3.

12.0 Performance tests

Except where otherwise stated in these specifications, the following requirements shall apply.

12.1 General

12.1.1 The applicable general and additional specific test requirements based on the technology, principle of measurement, feature or function of the device shall apply when conducting performance tests. (See Appendix B)

12.1.2 Each required test shall meet the requirements as specified in section 7.0, when applicable.

12.1.3 For electronic devices, each required test shall have no effect on the electronic indicator, stored data or the device's ability to interpret inputs from connected devices.

12.1.4 All influence quantities except for the influence quantity being tested shall remain constant during performance testing of a device.

12.2 Test conditions

12.2.1 Environmental conditions
  1. Ambient temperature
    1. Reference
      The ambient temperature shall be (20.0 ± 5.0) °C with a rate of change not greater than 0.5 °C per hour.
    2. "Other than reference"
      Meters shall be tested at ambient temperatures over the range from (−30 ± 2) °C to (40 ± 2) °C, except when they are intended for use in a temperature-controlled environment, in which case, they shall be tested over the range of ambient temperatures specified by the manufacturer.
  2. Atmospheric pressure
    The atmospheric pressure used in calculations shall be that prevailing at the time of testing.
  3. Relative humidity of ambient air
    The relative humidity of the ambient air shall be that prevailing at the time of testing.
12.2.2 Operating conditions
  1. Working temperature (tw)
    1. Reference
      The flowing gas temperature shall be measured at the inlet of the measuring instrument and shall be within ± 0.5 °C of the ambient reference temperature, unless temperature corrections are made.
    2. "Other than reference"
      The flowing gas temperature shall be measured at the inlet of the meter. Based on the environment type where the measuring instrument is intended for use, the following shall apply (see Part 1, Table 1).
      Part 1, Table 1: "Other than reference" working temperatures
      Environment type where the instrument is intended for use "Other than reference" ambient temperature "Other than reference" working temperature
      Non-temperature-controlled environment Low ambient temperature (-30 ± 2) °C -10 °C
      0 °C
      High ambient temperature (40 ± 2) °C 10 °C
      30 °C
      Temperature-controlled environment Low ambient temperature (Tmin) specified by the manufacturer 0.25 (Tmax - Tmin) + Tmin
      High ambient temperature (Tmax) specified by the manufacturer Tmax - 0.25 (Tmax - Tmin)
  2. Working pressure (pw)
    The flowing gas pressure shall be near atmospheric or the minimum operating pressure specified by the manufacturer, whichever is greater. In addition, measuring instrument may be tested at any pressure up to the maximum operating pressure.
  3. Humidity content of flowing gas
    The humidity content of flowing gas shall be such that no condensation occurs during testing.
  4. Density of dry air
    The density of dry air at standard temperature and standard pressure shall be taken as:
    1. 1.225 kg/m³; or
    2. 0.07654 lb/ft³.
  5. Moisture
    Means shall be employed to prevent the accumulation of moisture in the measuring instrument during testing.
    1. Depending on the dew point of the test gas, it may not be feasible to obtain some of the required temperature values. In these instances, the largest differential temperature obtainable shall be considered.
    2. The measuring instrument shall be subjected to the test temperatures for a length of time as is necessary to establish thermal stability.
12.2.3 Power source

Where a device is powered from the mains, the voltage shall be within ± 1% of the rated voltage and the frequency shall be within ± 0.2% of the rated voltage.

12.2.4 Flow rate test points

12.2.4.1 The flow rate at which the errors of the gas meters need to be determined shall be distributed over the measuring range at regular intervals and include Qmin and Qmax (also preferably Qt where applicable).

12.4.2.2 Based on the number of test points per decade (M), the minimum number (N) of test points, ranking from i = 1 to i = N shall be calculated according to the following equation:

N = 1 + M × log((Q max) ÷ (Q min))

Where,

12.2.4.3 For flow rates covering two decades or more, the following equation presents the distribution of flow rates for i = 1 to i = N-1 and QN = Qmin.

(Q i) = (M√10)^(1 - i) × (Q max)

Where,

12.2.4.4 The flow rate shall be within 5% of the value calculated in 12.3.3 except where otherwise stated in these specifications.

12.2.5 Test mediums

12.2.5.1 The test medium for the performance testing of the measuring instrument shall be the same as the medium the measuring instrument is intended to measure.Footnote 1-10

12.2.5.2Where the applicant suggests using alternative test mediums for performance testing, the applicant shall:

  1. contact MC and demonstrate that the performance testing can be done with an alternative medium, at alternative conditions, without introducing a bias.
    1. Otherwise, the performance testing shall be done at the measuring instrument's intended operating conditions.
  2. obtain MC's requirements for testing and test data submission for the evaluation of the use of the proposed test medium; and
  3. ensure the required testing is completed at a test facility recognized by MC and submit the results to MC for evaluation.

12.3 Evaluation tests

12.3.1 Location of data

Devices equipped with an electronic display shall be evaluated to determine if the display's reading is derived from the same memory location as the output signal used for gating the prover during accuracy testing.

12.3.2 Range of programmable parameters

12.3.2.1 Where a measuring instrument incorporates features which allow the user to set the range or operating parameters of the measuring instrument, it shall be tested over a range of such features sufficient to establish that the applicable requirements of these specifications are met throughout the range for which approval is sought.

12.3.2.2 All adjustments and recalibrations shall be performed according to the manufacturer's instructions.

12.3.3 Accuracy testing

The error of the measuring instrument shall be determined at test conditions as described in subsection 12.2.

12.3.4 Repeatability

12.3.4.1 At Qmin, Qt, and Qmax, the errors are determined three times and the difference between the minimum and maximum measured error is calculated.Footnote 1-11

12.3.4.2 Each measurement shall be of sufficient duration to provide an error resolution of 0.1% or better.

12.3.5 Orientation

12.3.5.1 Subject to 12.3.5.2, the applicant shall demonstrate that the measuring instrument is not orientation sensitive; otherwise, measuring instruments shall be tested in any orientations recommended by the manufacturer and for which approval is sought.

12.3.5.2 Where no specific mounting orientations are recommended, the accuracy measurements as specified in subsection 12.3.3 shall be performed in the following orientations:

  1. Horizontal;
  2. Vertical flow-up; and
  3. Vertical flow-down.

12.3.5.3 Where the requirements are not fulfilled for all prescribed orientations without intermediate adjustments, the NOA shall set out only the approved orientations.

12.3.6 Flow direction

12.3.6.1 Subject to 12.3.6.2, the accuracy measurements as specified in subsection 12.3.3 for gas meters designed for bidirectional measurement shall be performed without intermediate adjustments in both flow directions.

12.3.6.2 Where the requirements are not fulfilled for both flow directions without intermediate adjustments, the bidirectional gas meter shall be considered unidirectional and marked according to subsection 9.4, and such restriction shall be set out in any NOA issued by MC.

12.3.7 Flow disturbance

12.3.7.1 Subject to 12.3.7.2, where gas meter accuracy is susceptible to the installation configuration, the piping configuration shall be the one for which approval is sought that is most likely to cause an error in measurement.

12.3.7.2 Where a piping configuration has been identified, the installation being approved shall conform to the configuration identified or to one of the permissible configurations where more than one has been identified.

12.3.7.3 Where gas meter accuracy is not susceptible to the piping configuration, the configuration shall be the manufacturer's recommended configuration.

12.3.7.4 To evaluate the gas meter's swirl susceptibility, the following shall apply:

  1. The inlet to the installation configuration recommended by the manufacturer shall be preceded by a clockwise and a counter-clockwise swirl generator constructed of two ninety-degree elbows connected together orthogonally.
  2. The outlet of the upstream disturbance shall be placed a distance of two times the nominal pipe diameters from the upstream face of the gas meter.
  3. Downstream piping shall be straight and equal in diameter to the upstream piping and a minimum of two pipe diameters in length.
  4. At reference conditions, tests shall be performed at 0.25 Qmax, 0.4 Qmax and Qmax.
  5. A flow conditioner according to the manufacturer's specifications may be used to meet the requirements. In such a case, the flow conditioner shall be specified in the NOA.
  6. If a specific minimum length of straight upstream piping Lmin is necessary to meet the requirement, this Lmin shall be applied during the tests and its value shall be stated in the NOA.
12.3.8 Durability

12.3.8.1 The durability test shall apply to gas meters having a Qmax ≤ 800 ft³/h.

12.3.8.2 When a gas meter comes in various sizes and the design, composition and construction are proportional to its size and the pattern remains the same for the series, one meter shall be submitted for the durability test, except where requested otherwise by MC.

12.3.8.3 Subject to 12.3.8.4, durability tests shall be applied to gas meters where the highest wear is expected.

12.3.8.4 For gas meters with no moving parts in the measurement transducer, the smallest size shall be selected for durability tests.

12.3.8.5 The gas meter shall be subjected to a continuous flow rate between 0.8 Qmax and Qmax and comprising a quantity that is equivalent to a flow at Qmax during a period of 2,000 hours.

12.3.8.6 This test shall be performed at the minimum operating pressure.

12.3.8.7 The same reference equipment shall be used before and after the durability test.

12.3.8.8 After the durability test, the gas meter accuracy, as specified in subsection 12.3.3, shall be tested.

12.3.9 Vibration and shocks

12.3.9.1 Gas meters having a maximum mass of 10 kg shall be submitted to vibrations and shocks. For gas meters exceeding this weight, only the electronic part of the meter shall be tested.

12.3.9.2 Before and after these tests, the gas meter accuracy, as specified in subsection 12.3.3, shall be tested.

12.3.10 Supply voltage variation

12.3.10.1 Subject to 12.3.10.2, measuring instruments requiring power supply from the mains shall be tested, at reference ambient temperature, with a supply voltage equal to 85% and 110% of the nominal voltage.

12.3.10.2 Where an input voltage range is specified by the manufacturer, a typical voltage within this range shall be selected by MC in consultation with the manufacturer and be tested.

12.3.11 Influence of radiated radio frequency electromagnetic fields

Where the performance of measuring instruments may be affected by the presence of an electromagnetic field, they shall be subjected to the testing required in OIML R137-1, Annex A, section A.6.1.1 and the test results shall be supplied.

12.3.12 Electromagnetic interference susceptibility

Where the performance of measuring instruments may be affected by the presence of electromagnetic interference (EMI), they shall be subjected to testing required in OIML R137-1, Annex A, section A.6.1.2 and the test results shall be supplied.

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