PS-G-15 —Provisional specifications for the verification, installation and use of fluidic oscillation meters

Category: Gas
Specification: PS-G-15 (rev. 2)
Issue date: 2017-07-01
Effective date: 2017-07-01
Supersedes: PS-G-15 (rev. 1)

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Table of contents

• 1.0 Scope
• 2.0 Authority
• 3.0 References
• 4.0 Definitions
• 5.0 Metrological requirements
  • 5.1 Maximum permissible errors
    • 5.1.1 Accuracy tests
  • 5.2 Verification requirements
  • 5.3 Reverification requirements
• 6.0 Technical requirements
  • 6.1 Design, composition and construction
  • 6.2 Installation and use
• 7.0 Administrative requirements
  • 7.1 Markings
  • 7.2 Sealing
• 8.0 Revisions

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1.0 Scope

These provisional specifications apply to fluidic oscillation gas meters which operate by integrating gas flow through the detection of a gas jet's oscillation frequency.

2.0 Authority

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

3.0 References

• Electricity and Gas Inspection Act, section 9.
• Electricity and Gas Inspection Regulations, Part III
• Measurement Canada's generic inspection procedure for electronic volume conversion devices, Class 8, revision A, 2002-11-25
• S-G-03—Specifications for the approval of type of gas meters, ancillary devices and associated measuring instruments

4.0 Definitions

Deviation (écart)

The mean of the errors at a given flow rate.

Error (erreur)

The difference between the volume measured by the meter under test and the volume measure by a reference meter. Corrections must be made for the differences of gas pressure, temperature, and compressibility between the two meters. The error shall be calculated as follows:

$\mathrm{Error}(\%)=\frac{\left(\mathrm{volume at test meter}-\mathrm{volume at reference meter}\right)}{\mathrm{Volume at reference meter}}\times 100$

Fluidic oscillation meter (compteur à oscillateur fluidique)

A meter consisting of a body designed to condition gas flow into jet formation (flow conditioner and jet nozzle), a fluidic oscillation chamber (flow obstacle and sensors) and associated signal processing circuitry.

Flow weighted mean error (erreur moyenne pondérée au débit)

The flow rate weighted mean error of a meter calculated as follows:

$\mathrm{FWME }(\%)=(\underset{i=1}{\overset{n}{\Sigma }}\frac{Q_i}{Q_{max}}\times D_i\times W_i)÷\underset{i=1}{\overset{n}{\Sigma }}\frac{Q_i\times W_i}{Q_{max}}$

Where,

• Q_i is the test flow rate, and
• D_i is the deviation at the tested flow rate Q_i.

When Q_i ≥ 0.95 Q _max, W_i = 0.4, otherwise W_i = 1.0.

Linearity (linéarité)

The maximum difference between the meter's flow weighted mean error and any of the error deviations for test points between the maximum and minimum rated flow rates.

Maximum permissible error (erreur maximale tolérée)

The largest allowable deviation within the specified operational range of the meter.

Minimum flow rate, Q _min (débit minimal)

The minimum flow rate of a meter, as listed in the Notice of Approval.

Maximum flow rate, Q _max (débit maximal)

The maximum flow rate of a meter, as listed in the Notice of Approval.

Reference meter (compteur de référence)

A meter of known accuracy.

Repeatability (répétabilité)

The largest spread of errors of a given meter when several successive measurements are performed at the same flow rate under the same operating conditions.

5.0 Metrological requirements

5.1 Maximum permissible errors

5.1.1 Accuracy tests

5.1.1.1 Subject to clause 5.1.1.2, tests shall be conducted on a suitable test medium^{Footnote 1} at a pressure which is representative of the meter's intended use. Where Q _max cannot be achieved because of limitations of the test facility, the upper test flow rate shall be at least 0.4  Q _max and the meter shall be tested at least five flow rates approximately equally spaced between 0.1 Q _max and the Q _max attainable by the test facility.

The errors of the meter between Q _min and Q _max shall not exceed the following tolerances:

• Maximum permissible error: ±1.0%
• Repeatability: ±0.2%
• Linearity: ±0.3%

Where the meter's maximum test flow rate cannot be achieved, the errors of the meter shall not exceed the following tolerance limits:

Maximum permissible error: ±1.0% × % Q _max attained ÷ 100

where, % Q _max attained is the highest test flow rate attained.

5.1.1.2 Fluidic oscillation gas meters may be verified or reverified using appropriately certified proving technologies. Where fluidic oscillation gas meters are verified using a measuring apparatus which performs testing at low pressure using air as the test media, the test points shall be equal to 0.2  Q _max (± 0.05  Q _max) and 0.95 Q _max (± 0.05  Q _max). The test duration shall be sufficient to ensure an error resolution of 0.1% or better.

Maximum permissible error: ±1.0%.

Where the 0.95 Q_max (± 0.05  Q_max) test point cannot be achieved because of limitations of the test apparatus, the upper test flow rate shall be at least 0.5  Q_max, and the errors of the meter shall not exceed the following tolerance limits:

Maximum permissible error: ±1.0% × % Q _max attained ÷ 100

5.1.1.3 In addition to 5.1.1.1 and 5.1.1.2, where a meter contains one or more volume conversion functions, the meter shall be tested in accordance with the applicable requirements of Measurement Canada's generic inspection procedure for electronic volume conversion devices, Class 8, revision A, 2002-11-25 .

5.2 Verification requirements

5.2.1 The NOA shall be referred to for information regarding parameters in the processing circuitry which may need to be changed or programmed at the time of verification, and for sealing requirements.

5.2.2 Unless otherwise noted in the NOA, the volume indication on a meter's electronic display need not be verified by means of a volume accumulation test provided that a verification check is performed to ensure that the registered reading on the display matches the reading obtained using meter interrogation software.

5.3 Reverification requirements

Meters shall be submitted for reverification at least every six years. The requirements for reverification are the same as for verification.

6.0 Technical requirements

6.1 Design, composition and construction

The meter shall conform in every technical respect to the approved type as documented in the NOA.

6.2 Installation and use

6.2.1 The meter shall be installed in a manner designed to prevent accumulation of contaminants.

6.2.2 Unless otherwise stated in the NOA, the meter shall be installed either vertically or horizontally. In a vertically installed meter, the gas shall flow downward.

6.2.3 Where a meter is subject to flow pulsations and it has been shown that the meter's accuracy is affected by such disturbances, appropriate provisions shall be made to reduce the intensity of the disturbance to a level that will not induce a measurement error greater than the maximum permissible error specified in clause 5.1.1.1.

6.2.4 Where conditions of reverse flow may occur during meter usage, the installation shall incorporate provisions to prevent the reverse flow of gas.

6.2.5 The meter shall not be used outside the range of ambient temperature for which it is approved. Where necessary, shelter and heaters or other arrangements shall be provided to ensure that this requirement is met.

6.2.6 Only the approved meter outputs which are proportional to the volume of gas which has passed through the meter shall be used for billing calculations.

7.0 Administrative requirements

7.1 Markings

The meter shall be marked in full accordance with the markings section of the NOA.

7.2 Sealing

The verification marks for the meter shall take the form of a seal applied to prevent unauthorized access to metrological adjustments and shall be applied at the time of verification or reverification. The NOA should be referred to for any particular sealing requirements.

8.0 Revisions

8.1 The purpose of this revision is to:

• move all approval requirements to S-G-03;
• replace the reference to LMB-EG-08—Specifications for approval of type of gas meters and auxiliary devices with a reference to S-G-03. LMB-EG-08 has become obsolete.
• reformat the document according to new formatting requirements.

8.2 The purpose of the revision 1 was to remove requirements identified under the Government of Canada's paperwork burden reduction initiative.