S-G-08—Specification for the verification, reverification, installation and use of electronic volume conversion devices and functions

Category: Gas
Issue date:
Effective date:
Revision number: 1
Supersedes: N/A


Table of contents


1.0 Purpose

This specification establishes requirements for the verification, reverification, installation and use of EVC devices and functions approved by MC for use in trade measurement and custody transfer applications.

2.0 Scope

2.1 Types of electronic volume conversion devices and functions

This specification applies to EVC devices designed and intended for use with a single volumetric gas flow meter and to EVC functions built into volumetric gas flow meters.

These EVC devices and functions include a built-in pressure sensor and/or temperature sensor, which provide for volume conversion as a function of:

  • pressure only,
  • temperature only,
  • temperature with a fixed pressure multiplier,
  • pressure and temperature only,
  • pressure, temperature and supercompressibility.

These EVC devices and functions may also include a volume to energy conversion function.

2.2 Inspection location

Inspection of an EVC device or function must be conducted at:

  • a test facility, for the purpose of an initial verification,
  • a test facility or, if possible, at the device's operational location, for the purpose of reverification,
  • the operational location, for the purpose of an assessment of conformity with specified installation and use requirements.

2.3 Exclusions

This specification does not apply to the following devices:

  • temperature converting ultrasonic domestic gas flow meters of a type approved prior to January 1, 2003, and having an approved maximum flow rate not exceeding 250 ft3/h or the metric equivalent,
  • flow computers.

3.0 References

4.0 Authority

This specification is issued under the authority of section 18 of the Electricity and Gas Inspection Regulations.

5.0 Definitions

Base pressure, Pb (pression de base)
The reference value of pressure to which a volume of gas at a different pressure is converted.
Base temperature, Tb (température de base)
The reference value of temperature to which a volume of gas at a different temperature is converted.
Base volume (volume de base)
The volume of gas referenced to base pressure and base temperature.
Calorific value (pouvoir calorifique)
The amount of energy stored in a fixed unit of volume that is referenced to particular conditions of pressure and temperature (e.g. base conditions). Other terms used in legislation and the natural gas industry for this property include "calorific power", "energy density" and "heating value". For the purposes of this specification, the calorific value of a gas is its gross volumetric heating value established on a real, dry basis by measurement or calculation.
Configurable device (appareil configurable)
A device designed such that the information received from its measurement inputs can be selected and/or processed in different ways to suit different measurement applications. It includes any device that has been approved to permit legally relevant parameters to be deleted, appended to, modified, or substituted in whole or in part directly by the authorized operator or by a communication link from another device, such as a local or remote console or computer, whether or not the secondary apparatus is part of the network connecting the devices.
Configurable parameter (paramètre configurable)
Any adjustable or selectable parameter within a configurable device that can have an effect on the accuracy of a device or can significantly increase the potential for fraudulent use of the device and, based on its nature, may need to be updated on an ongoing basis, or only during device installation or upon replacement of a component.
Defect (défaut)
A departure of a meter's quality characteristic from its intended level or state that occurs with a severity sufficient to cause the meter to not satisfy normal usage requirements. Depending on its nature and severity, a defect may cause nonconformity to occur immediately or at some time in the future.
Electronic volume conversion device or function (dispositif ou fonction de conversion du volume électronique)
An electronic device or an electronic function built into a volumetric gas flow meter that converts a volume of gas at a particular pressure and temperature (e.g. flowing conditions) to the volume at base pressure and/or temperature. The device or function may also apply supercompressibility correction to account for the deviation of a real gas from the ideal gas law.
Event (événement)
An action during which one or more changes are made to a legally relevant parameter. Events include software updating and event log exporting.
Event log (registre d'événements)
A compilation of event records.
Event logger (consignateur d'événements)
A secure form of audit trail containing a series of records, where each record contains a number corresponding to a specific event.
Hash code (code haché)
A code calculated based on the contents of a subject. Hash codes can be used to demonstrate that the contents of a subject have not been modified.
Legally relevant (juridiquement pertinent)
Software, hardware, data or a part thereof which interferes with properties regulated by legal metrology.
Legally relevant parameter (paramètre juridiquement pertinent)
A parameter of a measuring instrument, an electronic device or a sub-assembly subject to legal control. Legally relevant parameters typically form part of the legally relevant functions performed by a device. The following types of legally relevant parameters can be distinguished: type-specific parameters and device-specific parameters. For the purposes of this specification, legally relevant parameters are those which are, either individually or as part of a function, subject to verification under the Electricity and Gas Inspection Act.
Measurand (mesurande)
A quantity intended to be measured.
Pressure multiplier, Pm (multiplicateur de pression)
A factor applied to a volume of gas at a particular pressure (e.g. flowing pressure) to convert it to the volume at base pressure. A electronic volume conversion device or function calculates a pressure multiplier using one of the following equations:

P m = ( P ga + P a ) P b or P m = P abs P b

Where,

  • Pga is the average flowing gas pressure measured on the gauge pressure scale
  • Pa is the atmospheric pressure
  • Pabs is the average flowing gas pressure measured on the absolute pressure scale
  • Pb is the base pressure
Relative error (erreur relative)
The 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, the relative error is calculated using the following equation:

E r ( Q m Q s Q s ) x 100 % = ( Q m Q s 1 ) x 100 %

Where,

  • Er is the relative error of the device under test, expressed as a percentage
  • 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
Reverification (revérification)
A subsequent confirmation of a meter's conformance to legal requirements following the initial confirmation of its conformance to those same requirements (i.e. verification) performed upon expiration of the meter's initial verification period and each subsequent reverification period.
Span (étendue de mesure)
The maximum value of a measuring range minus its minimum value.
Supercompressibility factor, Fpv (facteur de surcompressibilité)
A factor used to correct for a deviation from the ideal gas law when converting a volume of a gas at a particular pressure and temperature (e.g. flowing conditions) to the volume at base pressure and temperature. This deviation is due to the compressibility of a real gas, which varies in composition, pressure and temperature. The supercompressibility factor is used in non-linear metering applications (e.g. differential pressure-based metering) and the supercompressibility factor squared is used in linear metering applications (e.g. non-differential pressure-based metering).
Temperature multiplier, Tm (multiplicateur de température)
A factor applied to a volume of gas at a particular temperature (e.g. flowing temperature) to convert it to the volume at base temperature. As applicable, an electronic volume conversion device or function calculates the temperature multiplier using one of the following equations:

T m = ( T b + 459.67 ) ( T ga + 459.67 ) (Imperial system of units); or

T m = ( T b + 273.15 ) ( T ga + 273.15 ) (International system of units)

Where,

  • Tga is the average flowing gas temperature
  • Tb is the base temperature
Traced update (mise à jour traçable)
The procedure of changing legally relevant or legally non-relevant software in a verified device after which the subsequent verification by a responsible party is not necessary.
Ultrasonic domestic gas flow meter (débitmètre de gaz domestique à ultrasons)
An ultrasonic gas flow meter which includes a battery-powered register and associated processing circuitry, all enclosed within the same meter case and used to measure volumes of gas at working pressures up to a maximum of 200 kPa (or 29 lb per square inch).
Verification (vérification)
The operations carried out by an inspector or accredited organization to confirm that a meter entirely conforms to legal requirements.
Verification triggering event (événement déclencheur de vérification)
Any event deemed by Measurement Canada to require reverification of a device before it can be used or continue to be used in trade. An event logger's recording of a verification triggering event has the same ramifications and consequences as the breaking of a device's physical seal.

6.0 General

6.1 Approved range of measurement

Except where otherwise specified, any references in this specification to an EVC device or function's measuring range (including its minimum and maximum values) for pressure or temperature are to be considered as references to its approved range or a configured range within its approved range.

6.2 Conforming devices or functions

An EVC device that conforms to an approved type and to all applicable requirements of this specification is considered verified or reverified, as applicable.

A gas flow meter with a built-in EVC function must conform to an approved type and all applicable requirements of this and any other applicable specification to be considered verified or reverified, as applicable.

6.3 Nonconforming devices or functions

An EVC device or function that does not conform to all applicable requirements of this specification, or that possesses a defect that could affect its ability to satisfy normal usage requirements, is considered nonconforming and is not accepted for the purposes of verification or reverification.

6.4 Disposition of nonconforming devices

Nonconforming or defective EVC devices and functions may only be resubmitted for inspection after their deficient quality characteristics have been corrected.

6.5 Verification and reverification procedures

Inspection of EVC devices and functions for the purpose of verification or reverification is to be conducted in accordance with an inspection procedure developed by MC or authorized by MC for use by an accredited organization.

7.0 Administrative requirements

7.1 Marking requirements

7.1.1 Electronic volume conversion device

An EVC device must be marked clearly and legibly:

  • with an inspection or meter number assigned by the contractor,
  • with the notice of approval (NOA) number (except for a type approved prior to July 1987),
  • with the information indicated in the markings section of the NOA, and
  • in accordance with the applicable requirements of specification S-G-03.

7.1.2 Electronic volume conversion function

A gas flow meter with a built-in EVC function must be marked clearly and legibly with all the applicable EVC-related information indicated in the markings section of the NOA and required by specification S‑G‑03.

7.2 Legally relevant software version

The legally relevant software parts installed in an EVC device or function must be of a version that is indicated in its NOA.

7.3 Legally relevant software hash code

If an EVC device or function is approved with a traced update capability, the generated hash code for each installed legally relevant software part must match the hash code for the corresponding software part and version indicated in the NOA.

7.4 Interrogation hardware and/or software

If the NOA of an EVC device or function indicates specific interrogation hardware and/or software versions needed to access information required for inspection purposes, these versions are to be used by the inspector or accredited organization.

In addition, other interrogation hardware and/or software developed and/or recommended by the manufacturer of the EVC device or function may be used to facilitate the inspection.

7.5 Configurable devices and functions

If an EVC device or function is approved to permit certain legally relevant parameters to be reconfigured (i.e. deleted, appended to, modified or substituted) without requiring reverification, the following requirements apply:

  1. Subject to (b), any such parameters that the contractor or device owner intends to reconfigure following verification and sealing must be inspected and verified in accordance with the applicable requirements of this specification.
  2. If a legally relevant function is indicated in the device's NOA as being approved to permit the use of configurable parameters within an approved range, all discrete values of such parameters within the approved range are legally relevant and are considered inspected and verified when the function is inspected and verified.

Note: If the contractor or the device owner does not inform the inspector or accredited organization that they intend to reconfigure the legally relevant parameters after the EVC device or function is verified and sealed, they risk triggering a device reverification if they switch from a verified to an unverified legally relevant parameter.

7.6 Inspection certificate or record of inspection

The following requirements apply:

  1. Subject to (b), an inspection certificate issued pursuant to section 14 of the Electricity and Gas Inspection Act for each verified or reverified EVC device or gas flow meter with a built-in EVC function must include the information prescribed in section 21 of the Electricity and Gas Inspection Regulations as well as the following additional information:
    • A version identifier for each legally relevant software part.
    • A generated hash code for each legally relevant software part (if approved with a traced update capability).
    • Legally relevant parameters that may be reconfigured without triggering a reverification of the device, except for those used by legally relevant functions of the type described in 7.5(b).
    • All test results, including those associated with any legally relevant parameters indicated by the contractor in 7.5(a).
  2. If the inspection is conducted by the device owner, the record of inspection is to include the information listed in item (a).
  3. As applicable, the inspection certificate or record of inspection will serve as objective evidence of inspection for any legally relevant parameters indicated in the NOA as capable of being reconfigured without requiring reverification of the device. Such objective evidence is to be provided to MC upon request.

7.7 Reverification periods

The initial and subsequent reverification periods for EVC devices and gas flow meters with a built-in EVC function are established in bulletin G-18. EVC devices that have qualified to be granted a conditionally or unconditionally lengthened initial reverification period are indicated in bulletin G-03.

8.0 Technical requirements

8.1 General

An EVC device or function must conform in every respect to the approved type described in its NOA and be free of any:

  • physical damage or defect which could affect its ability to satisfy normal usage requirements, and
  • dirt, debris or other foreign substance, both internally and externally, which could affect its ability to satisfy normal usage requirements.

8.2 Electronic display

An EVC device or function's electronic display must be clearly readable with no missing segments or annunciators. A full segment test is to be performed if the device or function provides for it.

8.3 Leakage

Any part of an EVC device or function that is intended to contain gas must operate without leakage at any pressure up to the manufacturer's maximum rated pressure.

8.4 Communication interface

If an EVC device or function's communication interface is approved as the sole means of accessing certain information required for type approval and/or verification purposes, it must function as intended and as approved. Such information may include the firmware version, information normally marked on a nameplate, legally relevant parameters, volume conversion multipliers and event log contents.

8.5 Event logger

If an EVC device or function is approved to permit certain legally relevant parameters to be reconfigured without requiring its reverification, the functionality of its event logger is to be confirmed by reconfiguring at least one such legally relevant parameter as indicated in the NOA.

8.6 Telemetering functions or devices

8.6.1 Built-in pulse generator

Except where otherwise authorized by MC, the following requirements apply:

  • Each activated pulse generator associated with a legal unit of measure (e.g. unconverted volume, converted volume, energy) is subject to inspection.
  • A deactivated pulse generator is not subject to inspection if it can only be reactivated by breaking a physical seal.
  • A deactivated pulse generator is subject to inspection if the contractor or device owner intends to reactivate it following verification and sealing, and this reactivation is recorded by an approved event logger.
  • A volume accumulation is required to confirm that the number of pulses produced is correct and consistent with the registered accumulated volume, configured volume per pulse, and configured registered volume multiplier.
  • As applicable, an energy accumulation is required to confirm that the number of pulses produced is correct and consistent with the registered accumulated energy, configured energy per pulse, and configured registered energy multiplier.
  • No error is permitted in the number of volume or energy pulses produced for volume and/or energy accumulations.

8.6.2 Automatic meter reading device or function

The following requirements apply:

  • An automatic meter reading (AMR) device retrofitted to an EVC device or a gas meter with a built-in EVC function must be of an approved type.
  • Except where otherwise authorized by MC, a built-in AMR function or retrofit-type AMR device is subject to inspection. However, specified requirements for their verification or reverification are outside the scope of this specification.

9.0 Metrological requirements

9.1 Calibration target

The calibration target of an EVC device or function's pressure and/or temperature measurement must be as close to the conventional true value (i.e. zero absolute error) as its adjustment will allow over the applicable measuring range.

9.2 Device or function configuration

The following requirements apply:

  • Prior to being presented for inspection, an EVC device or function is to be configured:
    • for its intended use in service by the contractor,
    • with approved legal units of measure for volume and/or energy, as applicable,
    • with an approved standard and method of calculation for supercompressibility correction as indicated in the NOA (as applicable),
    • with a fixed calorific value or an approved standard and method of calculation of calorific value as indicated in the NOA (as applicable), and
    • with the same base pressure and base temperature for the volumetric component of the calorific value as those used for converted volume, or with one or more conversion factors that correctly account for any difference between these base conditions (as applicable).
  • As applicable and required, the device or function is to be reconfigured to provide for performance testing of any legally relevant functions and/or parameters that the contractor intends to reconfigure in service following verification and sealing.
  • Upon successful completion of the inspection, the device or function is to be reconfigured for its intended use in service prior to sealing.

Note: Where applicable, an EVC device or function's event logger should log each legally relevant parameter that is reconfigured during the inspection process. The event log and the inspection certificate and/or record will serve as objective evidence of the verification of the reconfigured legally relevant parameters.

9.3 Performance testing requirements

9.3.1 Pressure and temperature standards

Performance testing of an EVC device or function is to be conducted using appropriately selected working level pressure and temperature standards that have valid calibration certificates with traceability to national standards (or as may be alternatively authorized by MC).

9.3.2 Test pressure and temperature stability

During performance testing of an EVC device or function, the applied test pressure must not vary by more than ±0.1% of the target value, and the applied test temperature must not vary by more than ±0.3 °F (±0.2 °C), as applicable.

9.3.3 Minimum test quantity

Accumulations of converted volume and energy must be of a sufficient quantity to ensure 0.1% resolution in the calculation of the performance test result. The minimum test quantity (Q) is to be calculated as follows:

Q = ΔQ % resolution x 100 %

Where,

  • ΔQ is the device or function's smallest measurable or readable quantity, as applicable
  • % resolution is the resolution required in the calculation of the test result

9.3.4 Use of gas measurement software applications

Any software application used to calculate the conventional true values of a supercompressibility factor or calorific value must be evaluated and authorized for inspection purposes by MC’s senior gas engineer.

Any software application used for any other calculations and/or compliance assessments must be evaluated and authorized for inspection purposes by MC’s regional gas specialist or senior gas engineer.

9.3.5 Application of performance testing requirements

This specification's performance testing requirements apply to EVC devices or functions as follows:

  • Subsection 9.3.6 applies in all cases, except where an EVC function is built into a gas flow meter, and where an EVC device and gas flow meter are to be inspected and sealed as a single device.
  • Subsections 9.3.7, 9.3.8 and 9.3.9 apply (subject to the conversion type) if an EVC device or function's pressure multiplier or pressure, temperature multiplier or temperature, and supercompressibility factor squared (Fpv2) or supercompressibility factor (Fpv), are accessible via the electronic display or interrogation hardware and/or software.
  • Subsection 9.3.10 applies to all EVC devices and functions, except an EVC function built into temperature converting ultrasonic domestic gas flow meters having an approved maximum flow rate not exceeding 1700 ft³/h.
  • Subsection 9.3.11 applies to EVC devices and functions with approved legal units of measure for energy.

9.3.6 Unconverted volume registration

An EVC device's mechanical and/or electronic registration of unconverted volume is to be tested in accordance with the following requirements:

  1. A single volume accumulation test is required using a rate of volumetric input that does not exceed the maximum value indicated in the NOA or specified by the manufacturer.
  2. If the device detects instrument drive revolutions or low frequency pulses the accumulation must be of a sufficient quantity to assess the device's mechanical and/or electronic registration of unconverted volume based on the following test parameters:
    • Number of applied revolutions or pulses;
    • Volume per revolution or volume per pulse configured in the device,
    • Volume per revolution marked on the mechanical index; and/or
    • Unconverted volume multiplier configured in the device;
  3. If the device detects high frequency pulses or a flow meter’s impeller shaft revolutions (via a magnetic coupling), the accumulation test must be of a sufficient quantity to ensure 0.02% resolution in the calculation of the performance accuracy (expressed as a relative error) of its registered unconverted volume.

9.3.7 Pressure multiplier

The performance accuracy of an EVC device or function's pressure multiplier is to be tested in accordance with the following requirements:

  1. If the device or function's pressure multiplier is not readily accessible, its apparent pressure multiplier may be calculated and tested using the applicable pressure multiplier equation in section 5.0, and the device or function's indicated gauge or absolute pressure (as applicable), configured atmospheric pressure (as applicable) and base pressure.
  2. A performance test is required at each test point specified in Table 1.
    Table 1: Pressure test points
    Test point designation Pressure test points (percentage of span)
    P1 20 ± 2
    P2 50 ± 2
    P3 80 ± 2
  3. The test pressure for a specified test point is to be calculated as follows:

    Test pressure = ( test point 100 x ( P max P min ) + P min ) ± ( 0.02 x ( P max P min ) )

    Where,

    • Test point is the pressure test point specified in Table 1
    • Pmax is the maximum value of the device or function's pressure measuring range
    • Pmin is minimum value of the device or function's pressure measuring range
  4. If the device or function measures absolute pressure and the calculated test pressure for the P1 test point is less than local atmospheric (i.e. barometric) pressure, the test is to be conducted at atmospheric pressure.

9.3.8 Temperature multiplier

The performance accuracy of an EVC device or function's temperature multiplier is to be tested in accordance with the following requirements:

  1. If the device or function's temperature multiplier is not readily accessible, its apparent temperature multiplier may be calculated and tested instead using the applicable equation in section 5.0, and the device or function's indicated temperature and configured base temperature.
  2. An EVC device or function that only measures temperature may have its indicated temperature tested as an alternative to its temperature multiplier or apparent temperature multiplier.
  3. Subject to (d), a performance test is required at each test point specified in Table 2.
    Table 2: Temperature test points
    Test point designation Temperature test points
    T1 30 ± 2 °C (86 ± 4 ºF)
    T2 15 ± 2 °C (59 ± 4 ºF)
    T3 0 ± 2 °C (32 ± 4 ºF)
  4. A single performance test may be conducted using a temperature between the T1 and T3 test points specified in Table 2, provided the device or function does not have a supercompressibility correction function and a maximum pressure exceeding 300 psig or psia, or the metric equivalent.
  5. An accredited organization testing EVC devices and functions in accordance with d. must identify the temperature test point they are using in their accreditation documentation (e.g. inspection procedure) and inspection certificates or records.

9.3.9 Supercompressibility correction function

The performance accuracy of an EVC device or function's supercompressibility correction function is to be tested in accordance with the following requirements:

  1. If the device or function's Fpv2 is not readily accessible, the test may be conducted using its Fpv.
  2. Subject to (c), a performance test is required at each test point combination specified in Table 3.

    Table 3: Supercompressibility correction test points
    Test point combinations Pressure test points (% of span) Temperature test points
    P1 and T1 20 ± 2 30 ± 2 °C (86 ± 4 ºF)
    P2 and T2 50 ± 2 15 ± 2 °C (59 ± 4 ºF)
    P3 and T3 80 ± 2 0 ± 2 °C (32 ± 4 ºF)
  3. A single performance test may be conducted at the P3 and T3 test point combination, provided the device or function's maximum pressure does not exceed 300 psig or psia, or the metric equivalent.

9.3.10 Volume conversion function

The performance accuracy of an EVC device or function's volume conversion function is to be tested in accordance with the following requirements:

  1. Subject to (b), a single volume accumulation is required for test No. 1 as specified for the applicable conversion type in Table 4, or as specified in Table 5 if the testing in 9.3.8 is conducted using a single temperature only.
  2. If the device or function’s pressure multiplier or pressure, temperature multiplier or temperature, and Fpv2 or Fpv are not accessible (subject to the conversion type), a volume accumulation is required for each test number specified for the applicable conversion type in Table 4, or alternatively specified in Table 5 for single temperature testing.
    Table 4: Volume conversion test points and maximum permissible errors
    Conversion type Test
    No.
    Test point combinations Pressure
    test points
    (% of span)
    Temperature
    test points
    Maximum permissible
    error
    Pressure only
    • 1
    • 2
    • 3
    • P3
    • P2
    • P1
    • 80 ± 2
    • 50 ± 2
    • 20 ± 2
    N/A ± 1.0%
    Temperature only
    (with or without fixed Pm)
    • 1
    • 2
    • 3
    • T3
    • T2
    • T1
    N/A
    • 0 ± 2 °C (32 ± 4 °F)
    • 15 ± 2 °C (59 ± 4 °F)
    • 30 ± 2 °C (86 ± 4 °F)
    ± 1.0%
    Pressure and temperature only
    • 1
    • 2
    • 3
    • 4
    • 5
    • P3 and T3
    • P2 and T2
    • P1 and T1
    • P3 and T1
    • P1 and T3
    • 80 ± 2
    • 50 ± 2
    • 20 ± 2
    • 80 ± 2
    • 20 ± 2
    • 0 ± 2 °C (32 ± 4 °F)
    • 15 ± 2 °C (59 ± 4 °F)
    • 30 ± 2 °C (86 ± 4 °F)
    • 30 ± 2 °C (86 ± 4 °F)
    • 0 ± 2 °C (32 ± 4 °F)
    ± 1.4%
    Pressure, temperature and supercompressibility
    • 1
    • 2
    • 3
    • 4
    • 5
    Same as above Same as above Same as above ±1.5%
    Table 5: Alternate volume conversion test points and maximum permissible errors
    Conversion type Test No. Test point combinations Pressure test points (% of span) Temperature test
    point
    Maximum permissible error
    Temperature only (with or without fixed Pm) 1 T N/A Single point within
    T1 and T3 test points specified in Table 4
    ±0.5%
    Pressure and temperature only
    • 1
    • 2
    • 3
    • P3 and T
    • P2 and T
    • P1 and T
    • 80 ± 2
    • 50 ± 2
    • 20 ± 2
    Single point within
    T1 and T3 test points specified in Table 4
    ±1.1%
    Pressure, temperature and supercompressibility
    (if Pmax ≤ 300 psi)*
    • 1
    • 2
    • 3
    • P3 and T3
    • P2 and T3
    • P1 and T3
    • 80 ± 2
    • 50 ± 2
    • 20 ± 2
    0 ± 2 °C (32 ± 4 °F) ± 1.1%

    * Single temperature testing doesn't apply to EVC devices or functions having supercompressibility correction and a maximum pressure exceeding 300 psig or psia, or the metric equivalent.

  3. The rate of volumetric input applied to the device or function must not exceed the maximum value indicated in the NOA or specified by the manufacturer.

9.3.11 Volume to energy conversion

The performance accuracy of an EVC device or function's unconverted volume to energy conversion function is equivalent to the overall performance accuracy of its volume conversion function and base volume to energy conversion function combined. This performance accuracy is to be tested in accordance with the following requirements:

  1. A single energy accumulation is required using the pressure and temperature test point combination that was used for test No. 1 of the volume conversion function in 9.3.10.
  2. As applicable, the conventional true value of the calorific value is:
    • the fixed value configured in the device or function, or
    • to be calculated using a software application authorized for use by MC as well as the device or function's configured standard and method of calculation of calorific value, gas composition parameters, base pressure, base temperature and units of measure.

9.4 Maximum permissible errors

9.4.1 Unconverted volume registration

If the device detects instrument drive revolutions or low frequency pulses, no error is permitted in its mechanical and/or electronic registration of unconverted volume. If it detects high frequency pulses or a flow meter's impeller shaft revolutions, the test result (expressed as a relative error) must not exceed a maximum permissible error (MPE) of ±0.2%.

9.4.2 Pressure multiplier

The performance accuracy (expressed as a relative error) of an EVC device or function's pressure multiplier or apparent pressure multiplier (as applicable) must not exceed an MPE of ±1.0%.

9.4.3 Temperature multiplier

The following performance requirements apply:

  1. Subject to (b), the performance accuracy (expressed as a relative error) of an EVC device or function's temperature multiplier or apparent temperature multiplier must not exceed an MPE of:
    • ±1.0% when tested at three temperatures; or
    • ±0.5% when tested at a single temperature.
  2. If the indicated temperature of an EVC device or function that only measures temperature is tested, the device or function's performance accuracy (expressed as an absolute error) must not exceed an MPE of:
    • ±2.8 °C (±5.0 °F) when tested at three temperatures; or
    • ±1.4 °C (±2.5 °F) when tested at a single temperature.

9.4.4 Supercompressibility correction function

The performance accuracy (expressed as a relative error) of an EVC device or function’s Fpv2 or the square of its Fpv must not exceed an MPE of:

  • ±0.1% if its maximum pressure does not exceed 300 psig or psia, or the metric equivalent, or
  • ±0.2% otherwise.

9.4.5 Volume conversion function

The following performance requirements apply:

  1. The performance accuracy (expressed as a relative error) of an EVC device or function's volume conversion function must not exceed the MPE specified for the conversion type tested in accordance with Table 4 or 5, whichever was used for performance testing.
  2. For EVC devices or functions that measure pressure and temperature but do not apply supercompressibility correction, the sum of the test result of any pressure multiplier (or apparent pressure multiplier) and of any temperature multiplier (or apparent temperature multiplier) must not exceed an MPE of:
    • ±1.4% if tested using three temperatures, or
    • ±1.1% if tested using a single temperature.

9.4.6 Volume to energy conversion function

The following performance requirements apply:

  1. If an EVC device or function is configured to apply a fixed calorific value, no error is permitted in its base (i.e. converted) volume to energy conversion function.
  2. If an EVC device of function is configured to calculate a calorific value, the performance accuracy (expressed as a relative error) of its base volume to energy conversion function must not exceed an MPE of ±0.10%.

    Note: An EVC device or function's base volume to energy conversion function is a calculator function that is assessed during type approval evaluation. Therefore, any nonconforming performance may be due to a configuration error, an incorrect interpretation of its configuration, or a combination of both. The inspector or accredited organization should confirm the validity of the performance test result before concluding on its conformity.

  3. The performance accuracy (expressed as a relative error) of the device or function's unconverted volume to energy conversion:
    • is the sum of any test result established for the volume conversion function in 9.3.10 and the test result (expressed as a relative error) established for the base volume to energy conversion function in 9.3.11, and
    • must not exceed the MPE applied to the volume conversion function test results established in 9.3.10.

10.0 Acceptance sampling inspection requirements

For future use.

11.0 Compliance sampling inspection requirements

11.1 Maximum permissible errors

The reverification period of an isolated lot of in-service electronic temperature converting (TC) modules may be extended using compliance sampling inspection in accordance with the applicable requirements of S-S-06 and the requirements of this specification.

Note:An electronic TC module can be one of the following:

  • An EVC device or module designed and intended for use with a single volumetric gas flow meter, providing only volume conversion as a function of temperature and having its own notice of approval and its own reverification period.
  • An EVC function approved by MC as an interchangeable component of a volumetric gas flow meter, providing only volume conversion as a function of temperature and that is verified and sealed as an interchangeable component of the host meter with its own reverification period.

 

11.2 Sampling inspection requirements

11.2.1 Sample selection

Each electronic TC module included in the sample must meet the following criteria, which take precedence over those stated in S-S-06:

  • be currently installed in service;
  • its metrological parameters must not have been adjusted post installation, unless one of the following applies:
    • the conditions stated in 14.0(g) are met; or
    • a temporary permission to place it into service without sealing is granted and the owner provides objective evidence that the modifications, if any, are not considered to be verification triggering events;
  • meet the homogeneity requirements stated in subsection 11.3 below; and
  • meet the total time on test requirements of S-S-06.

11.3 Requirements for lot and sample homogeneity

11.3.1 Lot homogeneity

Except where otherwise authorized by MC, electronic TC modules in the lot must be homogeneous with respect to the applicable characteristics specified in S-S-06 as well as the ones listed below:

Note:The characteristics listed below that are followed by an asterisk (*) apply, unless otherwise authorized in accordance with the requirements for lot formation of mixed meters specified in S-S-06.

  • same volumetric input characteristics (e.g. rate, volume per revolution or volume per pulse)*
  • approved features (i.e. traced update capability and configurable device);
  • same or similar configurations (e.g. intended use in service, legally relevant parameters configured);*
  • same type of telemetering functions (if so equipped);*
  • same test point combination used during the previous inspection of the volume conversion function (i.e. one or three temperature test points);
  • sealing status (modules that are granted temporary permission to be placed into service without sealing are not to be considered homogeneous with respect to modules excluded from such temporary permission);
  • battery characteristics (i.e. manufacturer, model, year of manufacture, easily accessible for exchange, and replaceable or not without being considered to be a verification triggering event)*

11.4 Metrological requirements

11.4.1 Performance testing

The performance accuracy of an electronic TC module's volume conversion function must be tested as per the testing performed at the previous inspection of the subject unit.

11.4.2 Performance test limits

An electronic TC module must be designated as a type 1 (C1) marginally conforming module or type 2 (C2) nonconforming module based on the performance error of its volume conversion function and the temperature test point combination, as follows:

Table 6: Compliance sampling performance test points and limits
Test No. Test point combinations Temperature test points Designation and
performance test limits
1 T Single point within T1 and T3 test points as specified in 9.3.8(d) Type 1 (C1): ± 0.9%
Type 2 (C2): ± 1.3%
  • 1
  • 2
  • 3
  • T3
  • T2
  • T1
Test points specified in Table 2 Type 1 (C1): ± 1.4%
Type 2 (C2): ± 2.1%

12.0 Sealing requirements

Except where otherwise authorized by MC, a verified or reverified EVC device or gas flow meter with a built-in EVC function is to be sealed and secured in accordance with the provisions of its NOA and the requirements of provisional specification PS-EG-02. Where an EVC device and a gas flow meter are inspected and verified as a single device, a verification seal is required to secure them to each other.

13.0 Installation requirements

A verified or reverified EVC device or gas flow meter with a built-in EVC function is subject to the following installation requirements:

  • The device or gas flow meter must be installed in accordance with any instructions and/or conditions included in the NOA, or as otherwise recommended by the manufacturer.
  • The device or function must accumulate unconverted volume in the correct direction when physically attached to a gas flow meter's instrument drive (as applicable).
  • As applicable, the device or function's temperature sensor must be located and installed in accordance with any instructions and/or conditions included in the NOA, or as otherwise recommended by the device or gas flow meter manufacturer.
  • As applicable, the device or function's installation must provide for isolation of its pressure sensor from line pressure.
  • The device or function's installation must provide for connection of a pressure standard to facilitate in situ performance testing.

14.0 Use requirements

A verified or reverified EVC device or an EVC function built into a verified or reverified gas flow meter, is subject to the following use requirements:

  1. The device must be used with an approved and compatible gas flow meter.
  2. The device or function must be used within its approved ranges for:
    • ambient temperature,
    • flowing gas pressure (as applicable),
    • flowing gas temperature (as applicable),
    • rate of volumetric input (or as otherwise specified by the manufacturer if not indicated in its NOA).
  3. Subject to (d), the device's marked and/or configured volumetric input parameter (e.g. volume per revolution or volume per pulse) must match the marked volumetric output parameter of the gas flow meter it is used with.
  4. If the device is configured with the equivalent metric value of the associated flow meter's volumetric output parameter (e.g. K factor), no error is permitted in the metric conversion calculation.
  5. The number of digits and multipliers configured in the EVC device or function for its indication of volume and/or energy must be sufficient to ensure the indicated readings are not repeated within a ninety-day period.
  6. If the device is used with a flow meter's temperature converted volumetric output (e.g. rotary meter with a temperature converting instrument drive), it must either be a non-temperature converting device or have its temperature multiplier configured with a fixed value of 1. The contractor must ensure temperature conversion is not inadvertently applied twice (i.e. by the source meter and the EVC device) when using an EVC device in such an application.
  7. Except where otherwise authorized by MC, reconfiguration of an in-service device's legally relevant parameters is only permissible if the following conditions are satisfied:
    • The device is approved to permit legally relevant parameters to be deleted, appended to, modified or substituted, in whole or in part, directly by an authorized entity (locally or remotely) without requiring device reverification (in accordance with specifications S-EG-05 and S-EG-06).
    • Any legally relevant parameter to be modified is indicated in the device or function's NOA as being capable of being reconfigured without requiring a reverification of the device.
    • The reconfiguration involves switching from one previously verified legally relevant parameter to another.
    • The reconfiguration is performed by a party that is authorized by the contractor.
  8. Upon request by MC, and as applicable, the contractor is required to provide access to the contents of a device or function's event logger and objective evidence of its previous inspection (i.e. inspection certificate or record).
  9. Subject to (g), if the device or function is used in a pressure factor metering installation, it may be configured with a fixed pressure multiplier value (i.e. contract value) if this capability is indicated in its NOA as being approved for such use. The contractor must ensure the pressure multiplier is not inadvertently applied twice (i.e. by the EVC device and the billing department) in such an application.
  10. Subject to (g), and as applicable, the device must be used with configured gas composition and/or gas property values (e.g. specific gravity / relative density or calorific value) that are traceable to an approved gas analysis device and are representative of the flowing gas being metered. Upon request by MC, the contractor is required to provide objective evidence of the traceability of configured gas parameters and of their being representative of the flowing gas being metered.
  11. Any modification of the device's volume and/or energy values is deemed a verification triggering event.
  12. Any adjustment, modification or exchange made to the device or function's calibration and/or hardware components is deemed a verification triggering event.
  13. Reconfiguration of the device or function's legally non-relevant parameters and legally non-relevant functions is permissible, provided it has no impact on the device's legally relevant functions, performance or verification status (e.g. breaking a verification seal).

15.0 Revisions

The purpose of revision 1 was to:

  • add compliance sampling inspection requirements in section 11.0; and
  • make some editorial changes to the text.