S-G-07—Specifications for the approval, verification, reverification, installation and use of electronic gas metering devices incorporating mass to base volume and/or energy conversion functions

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


Table of contents


1.0 Scope

These specifications apply to electronic gas metering devices incorporating a function or functions that convert their registered units of mass or mass flow rate, as measured by a Coriolis-type mass flow meter, to accumulated units of base volume and/or energy.

These specifications are intended to supplement all applicable requirements of existing specifications for the approval, verification, reverification, sealing, installation and use of the aforementioned gas metering devices.

2.0 Authority

These specifications are established under the authority of sections 12 and 18 of the Electricity and Gas Inspection Regulations.

3.0 References

4.0 Definitions

Base volume (volume de base)

The volume of gas referenced to base conditions of pressure and temperature (e.g. 101.325 kPa and 15 °C).

Density (masse volumique)

The mass of gas occupied by a fixed unit of volume referenced to particular conditions of pressure and temperature (e.g. base conditions).

Energy density (densité d'énergie)

The amount of energy stored in a fixed unit of volume referenced to particular conditions of pressure and temperature (e.g. base conditions). For the purposes of this document, the energy density of the gas is to be its gross volumetric heating value established on a real, dry basis by measurement or calculation.

Mass to base volume conversion function (fonction de conversion des unités de masse en unités de volume de base)

A function incorporated into an electronic gas metering device that converts its registered units of mass or mass flow rate to accumulated units of base volume based on the relations expressed in equations 1 or 2:

Equation 1

Vb = Qm × t ÷ ρb

Equation 2

Vb = m ÷ ρb

Where:

  • Vb is the accumulated units of base volume
  • Qm is the mass flow rate registered by the device
  • t is the time interval period for integration of mass flow rate
  • m is the accumulated units of mass registered by the device
  • ρb is the density of the gas referenced to base conditions of pressure and temperature calculated by the device
Mass to energy conversion function (fonction de conversion des unités de masse en unités d'énergie)

A function incorporated into an electronic gas metering device that converts its registered units of mass or mass flow rate to accumulated units of energy based on the relations expressed in equations 3 or 4:

Equation 3

E = (Qm × t ÷ ρb) × ED = Vb × ED

Equation 4

E = (m ÷ ρb) × ED = Vb × ED

Where:

  • E is the accumulated units of energy
  • Qm is the mass flow rate registered by the device
  • t is the time interval period for integration of mass flow rate
  • m is the accumulated units of mass registered by the device
  • ρb is the density of the gas referenced to base conditions of pressure and temperature calculated by the device
  • Vb is the accumulated units of base volume
  • ED is the energy density of the gas referenced to base conditions of pressure and temperature either calculated by the device or received as a live input or a configured parameter
Operational location (lieu d'exploitation)

The location (e.g. metering station) at which a particular metering device or piece of equipment is installed and used.

Relative density (densité relative)

The ratio of the density of a gas to the density of air, each referenced to the same conditions of pressure and temperature (e.g. base conditions). Relative density may also be referred to as specific gravity within the natural gas industry.

Relative error (erreur relative)

The ratio of the absolute error of the quantity registered or indicated by the device under test to the actual or conventional true value of the quantity as shown in equation 5:

Equation 5

Relative error = (R - T) ÷ T × 100%

Where,

  • R is the quantity registered or indicated by the device under test
  • T is the actual or conventional true value of the quantity

5.0 General

5.1 Additional requirements

In addition to the requirements of these specifications, all devices incorporating mass to base volume and/or energy conversion functions are also subject to all applicable requirements of specifications for the type approval, verification, reverification, sealing, installation and use listed under section 3.0 that apply to the particular device type.

5.2 Location of verification and reverification testing

Verification or reverification of the device may be conducted at a test facility or, where practicable, at the device's operational location.

5.3 Location of installation and use assessment

Compliance with installation and use requirements is to be assessed at the device's operational location.

6.0 Administrative requirements

6.1 Type approval

6.1.1 Units of measurement of density

The density of the gas calculated by the device is to be expressed in SI units of kg/m³ and/or imperial units of lb/ft³.

6.1.2 Markings and accessibility of parameters

The value and units of those parameters listed below (whether fixed, configurable, received as live inputs or calculated) that are used by the device's mass to base volume and/or energy conversion functions are to appear on the device's nameplate or be accessible via electronic display, printer or interrogation software:

  1. Base pressure to which base volume and items (d) to (g) are referenced
  2. Base temperature to which base volume and items (d) to (g) are referenced
  3. Mole fraction or mole percent gas composition
  4. Relative density
  5. Density of air
  6. Density of gas
  7. Energy density

6.1.3 Verifiability of standard and/or method of calculation selected

Where the device is capable of calculating any of the parameters listed below using more than one standard and/or method, the one selected for use in service is to be readily apparent:

  1. Relative density
  2. Density of air
  3. Density of gas
  4. Energy density

6.2 Verification and reverification

6.2.1 Markings

The device is to be marked in full accordance with its notice of approval.

6.2.2 Sealing

Except where otherwise permitted, a device found to be in compliance with all applicable verification specifications is to be sealed and secured in full accordance with the provisions documented in its notice of approval.

6.3 Installation and use

Upon request by an inspector or the local Measurement Canada (MC) regional office, the contractor must provide the following information on each source gas analysis device as objective evidence of their approval and verification status:

  1. Make, model, serial number and approval number,
  2. Operational location,
  3. Copy of current inspection certificate.

7.0 Technical requirements

7.1 Type approval

7.1.1 Device inputs

The device must be capable of receiving and using:

  1. the type and range of output signals from a compatible, approved Coriolis-type mass flow meter, and
  2. the type and range of output signals representing gas composition data and/or gas properties (i.e. relative density and/or energy density) from a compatible, approved gas analysis device (e.g. gas chromatograph), and/or
  3. locally or remotely configured gas composition data and/or gas properties.

7.1.2 Calculation of density

The device's calculation of the density of the gas referenced to base conditions of pressure and temperature is to be in accordance with any of the following standards and/or methods:

  1. AGA Report No. 8 detailed characterization method,
  2. AGA Report No. 8 gross characterization methods,
  3. the relative density of the gas and the density of air as expressed in equation 6.
Equation 6

ρb = Gr × ρb(air)

Where:

7.1.3 Calculation of relative density and/or air density

Where applicable, the device's calculation of relative density and/or density of air is to be in accordance with standards and/or methods currently recognized by MC (e.g. GPA 2145, GPA 2172, AGA Report No. 8).

7.1.4 Calculation of energy density

Where applicable, the device's calculation of energy density is to be in accordance with standards and/or methods currently recognized by MC (e.g. GPA 2145, GPA 2172).

7.2 Verification and reverification

The device must conform in every technical respect to the approved type as documented in its notice of approval.

7.3 Installation and use

7.3.1 Installation of the device

Unless otherwise stated in the notice of approval, the device is to be installed in accordance with the manufacturer's instructions.

7.3.2 Use with a compatible meter

The device must be used with a compatible, approved and verified Coriolis-type mass flow meter.

7.3.3 Source of gas composition data and/or gas properties

The device is to use gas composition data and/or gas properties (i.e. relative density and/or energy density) received as a live input or as locally or remotely configured parameters from a compatible, approved and verified gas analysis device.

Note: There is an increased risk of significant error being introduced in the determination of accumulated units of base volume and/or energy when the device uses local or remotely configured gas composition data and/or gas properties that have been established using geographical zone-based gas sampling methods and/or online gas analysis devices. Therefore, contractors are reminded of their metering accuracy obligations as prescribed under the Electricity and Gas Inspection Act and to ensure gas composition data and/or gas properties used by the device are sufficiently representative of the gas being measured at its operational location.

7.3.4 Range of gas composition data

Where applicable, the gas composition data used by the device to calculate the density of the gas must fall within the individual component ranges documented or referenced within the device's notice of approval.

7.3.5 Approved standard and/or method of calculation

The device must use an approved standard and/or method, as identified in its notice of approval, to calculate the following parameters:

  1. Density of gas
  2. Relative density
  3. Energy density

7.3.6 Base conditions

All parameters used in the device's calculation of accumulated units of base volume and/or energy are to be referenced to the same base conditions of pressure and temperature.

8.0 Metrological requirements

8.1 Type approval

8.1.1 Conversion function accuracy

The accuracy of the device's mass to base volume and/or energy conversion functions are to be assessed for each recognized standard and/or method of calculation of gas properties (i.e. density of gas, relative density, and/or energy density) for which approval is sought.

8.1.2 Maximum permissible error—mass to base volume conversion

The relative error of the device's mass to base volume conversion function must not exceed a maximum permissible error of ±0.1%.

8.1.3 Maximum permissible error—mass to energy conversion

The relative error of the device's mass to energy conversion function must not exceed a maximum permissible error of:

  1. ±0.1%, where the energy density is received as a live input or configured parameter, or
  2. ±0.2%, where the energy density is calculated by the device using gas composition data received as a live input or configured parameters.

8.2 Verification and reverification

8.2.1 Conversion function accuracy

The accuracy of the device's mass to base volume and/or energy conversion functions is to be assessed as configured and intended for use.

8.2.2 Accuracy test resolution

Sufficient units of mass are to be accumulated by actual flow or by the simulation of mass flow to ensure the relative error of the device's mass to base volume and/or energy conversion functions may be resolved to the nearest 0.01%.

8.2.3 Maximum permissible errors

The maximum permissible errors specified in 8.1.2 and 8.1.3 are also applicable for verification and reverification purposes.

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