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

Category: Gas
Issue date: 2022-06-06
Effective date: 2022-06-06
Revision number: 1
Supersedes: S-G-07


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 verification, reverification, sealing, installation and use of the aforementioned gas metering devices.

2.0 Authority

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

3.0 References

4.0 Definitions

Base volume
(volume de base)

Volume of gas referenced to base conditions of pressure and temperature (e.g. 101.325 kPa and 15 ºC).

Calorific value
(pouvoir calorifique)

The amount of energy stored in a fixed unit of volume referenced to particular conditions of pressure and temperature (e.g. base conditions).

Note:

  1. Calorific value is also known as "energy density".
  2. For the purposes of these specifications, the calorific value of a gas is its gross volume basis calorific value (Hv) established on a real, dry basis by measurement or calculation.
Density
(masse volumique)

Mass of gas per unit of volume referenced to particular conditions of pressure and temperature (e.g. base conditions).

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

V b = Q m × t ρb

Equation 2

V b = 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 = Q m × t ρb × Hv = V b × Hv

Equation 4

E = m ρb × Hv = V b × Hv

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
  • Hv is the volume-basis calorific value 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)

Ratio of the weight of a volume of gas or gas mixture to that of an equal volume of air, each referenced to the same conditions of pressure and temperature (e.g. base conditions).

Note: "Relative density" may also be referred to as "specific gravity" within the natural gas industry.

Relative error
(erreur relative)

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 verification, reverification, sealing, installation and use 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 its 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 Markings

The device must be marked in full accordance with all applicable location, legibility and marking requirements of specification S-G-03 and with any additional marking requirements included in its notice of approval (NOA).

6.2 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 of its NOA and specification PS-EG-02, as applicable. Verification markings are to be applied to a visible location of the device where no sealing provisions are included in the NOA.

6.3 Installation and use

Upon request by an inspector or the 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:

  • Make, model, serial number and approval number
  • Operational location
  • Copy of current inspection certificate

7.0 Technical requirements

7.1 General

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

7.2 Installation and use

7.2.1 Installation of the device

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

7.2.2 Use with a compatible meter

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

7.2.3 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 calorific value) 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.

7.2.4 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 NOA.

7.2.5 Approved standard and/or method of calculation

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

  • Density of gas
  • Relative density
  • Calorific value

7.2.6 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 Conversion function accuracy

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

8.2 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%.

8.3 Maximum permissible errors

8.3.1 Mass to base volume conversion function

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

8.3.2 Mass to energy conversion function

The relative error of the device's mass to energy conversion function must not exceed a MPE of one of the following values:

  • ± 0.1%, where the calorific value is received as a live input or a configured parameter
  • ± 0.2%, where the calorific value is calculated by the device using gas composition data received as a live input or configured parameters

9.0 Revisions

The purpose of revision 1 was to:

  • remove all approval requirements and incorporate them into S-G-03,
  • replace the term "energy density" by "calorific value" to match the terminology used in the approval specification,
  • update the list of references (section 3.0).