S-G-04—Specifications for the verification, reverification, installation and use of flow conditioners used in gas measurement systems

Category: Gas
Issue date:
Effective date:
Revision number: 1
Supersedes: S-G-04, PS-G-01, PS-G-05, PS-G-10, PS-G-11, PS-G-12

Table of Contents

1.0 Scope

These specifications apply to flow conditioners used in natural gas custody transfer metering systems.

2.0 Authority

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

3.0 References

4.0 Definitions


The subsequent confirmation of a meter's conformance to legal requirements following the expiration of its initial or subsequent reverification period.


The initial confirmation of a meter's conformance to legal requirements..

5.0 General

5.1 Mandatory verifications and reverifications

Except where otherwise authorized, all flow conditioners used in custody transfer applications are subject to mandatory verifications and reverifications.

5.2 Inspection location

Inspection and testing of the flow conditioner, for the purposes of verification or reverification, must be conducted at the flow conditioner's operational location.

6.0 Administrative requirements

6.1 Marking requirements

6.1.1 General

The flow conditioner 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 the notice of approval. Where the Markings section of the flow conditioner's notice of approval makes reference to particular clauses of the original version of these specifications, they are superseded by the requirements of specification S-G-03.

6.1.2 Notice of approval number

Flow conditioners manufactured prior to February 2009 are not required to be marked in accordance with their notice of approval number prior to the field verification. After the flow conditioner has undergone a device manufacturer inspection or an on-site inspection and is found to comply with the design requirements, it must be marked in accordance with section 6.1.1.

6.2 Sealing requirements

The following requirements apply:

  1. Verified and reverified flow conditioners must be sealed in accordance with the provisions of their notice of approval and specification PS-EG-02, as applicable.
  2. Where the requirements of section 7.0 have been met, a field inspection mark must be applied on the top edge of each section of pipe in the piping configuration.

6.3 Reverification periods

The initial and subsequent reverification periods for flow conditioners are prescribed in bulletin G-18.

7.0 Technical requirements

7.1 Installation and use

7.1.1 General

The following requirements apply:

  1. Only approved flow conditioners can be used in custody transfer metering systems.
  2. The flow conditioner must conform in every material respect to the type approved and described in its notice of approval.
  3. The flow conditioner must be installed with the model or type designation and notice of approval number clearly visible, when viewed from the top of the pipe.

    Note: Where the flow conditioner is not of a flange mount type, the nameplate provides for the identification of the flow conditioner and its status with regards to the manufacturer's design requirements.

  4. The meter which is preceded by the flow conditioner in the piping configuration must be of a type that has been identified in the notice of approval.
  5. The piping configuration must conform to the installation requirements set out in the notice of approval for the type of meter the flow conditioner precedes.
  6. The size and schedule of the upstream pipe of the flow conditioner must correspond to the size and schedule marked on the flow conditioner.
  7. Where flow range limitations have been identified in the notice of approval, an evaluation of the installation must be done to determine if these limitations are exceeded. A record of this evaluation must be kept and made available to Measurement Canada upon request.

8.0 Revisions

The purpose of revision 1 is to:

Date modified: