S-G-03–Specifications for the approval of type of gas meters, ancillary devices and associated measuring instruments

Category: Gas
Issue date:
Effective date:
Revision number: 1
Supersedes: LMB-EG-08 and S-G-03


Part 4: Turbine meters

Table of contents


1.0 Scope

This part of the Specifications applies to axial flow turbine type gas meters submitted for approval.

2.0 Definitions

High operating pressure (pression de fonctionnement élevée)

Any gas or air pressure over 5000 kPa (≈720 psig).

Low operating pressure (pression de fonctionnement basse)

Any gas or air pressure below 400 kPa (≈50 psig).

Medium operating pressure (pression de fonctionnement moyenne)

Any gas or air pressure from 400 to 5000 kPa (≈50 to ≈720 psig).

Measurement cartridge (cartouche de mesure)

An internal assembly that is removable from some meters and includes the measurement components, but excludes the meter body.

Turbine meter (compteur à turbine)

A volume measuring gas meter (inferential type) in which the measurement of the gas flow is effected by a turbine blade assembly that is mounted in a case which rotates as the gas flows past the turbine blades. The turbine meter utilizes the force (kinetic energy) of the flowing gas to drive the measurement turbine blade.

3.0 Metrological requirements

The applicable requirements of Part 1, section 7.0 shall apply unless otherwise stated in this section.

3.1 Maximum permissible errors

The following MPEs shall apply to the uncorrected volume registration at any flow rate within the flow rate range for which approval is sought (see Part 4, Table 1).

Part 4, Table 1: Turbine meter maximum permissible errors
Test conditions Meter operating pressure type Flow rate (Q) MPE
Reference or "other than reference" Meter intended for low operating pressure QminQQt (where Qt ≤ 0.2 Qmax) ± 1.5%
Qt < QQmax (where Qt ≤ 0.2 Qmax) ± 1%
Meter intended for medium or high operating pressure QminQQmax ± 1%

3.2 Effect of swirl

Where a swirl exists at the inlet of the meter, the error of the uncorrected volume accumulation shall not exceed ±1% of the true volume at any flow rate within the flow rate range for which approval is sought.

3.3 Measuring cartridge interchangeability

The fault due to measuring cartridge interchangeability shall not be more than one third of the MPE applicable during evaluation, while the error shall in no case exceed the MPE for that range.

4.0 Technical requirements

In addition to the applicable requirements of Part 1, section 8.0 and Part 13, the following shall apply.

4.1 Pulse output

Where a meter is equipped with a pulse generator, the applicable requirements of Part 12 shall apply.

5.0 Marking requirements

In addition to the applicable requirements of Part 1, section 9.0, the following shall apply.

5.1 The K-factor and/or rotor factor(s) shall be marked on the nameplate, where applicable.

5.2 Where a meter is designed for operation with interchangeable cartridges, the markings required in Part 1, 9.1.3(a), (b), (c), (d) and (f) and subsection 9.4 shall appear on the meter case and the interchangeable cartridge.

5.3 Where change gears are provided, the number of teeth shall be permanently marked on each of the change gears in such a location as to be legible with the change gears in place.

6.0 Performance tests

The applicable requirements of Part 1, section 12.0 shall apply unless otherwise stated in this section.

6.1 Test conditions

6.1.1 Operating conditions
6.1.1.1 Reference and "other than reference" working pressures (pw)
  1. Where gas meters are intended to operate at low pressure, the flowing gas pressure shall be near atmospheric.
  2. Where gas meters are intended to operate at medium pressure, the flowing gas pressure shall be approximately minimum and maximum operating pressure.
  3. Where gas meters are intended to operate at high pressure, the flowing gas pressure shall be any pressure equal or above 5000 kPa (720 psig).
6.1.2 Flow rate test points

For each flow rate at which the meter is tested, the peak-to-peak fluctuations in flow rate shall be minimized and in no case shall exceed 2% of the average flow rate.

6.1.3 Test medium

6.1.3.1 Where gas meters are intended to operate at low pressure, the test medium shall be air.

6.1.3.2 Where gas meters are intended to operate at medium and/or high pressure, the test medium shall be natural gas.Footnote 4-1

6.2 Temperature measurement

The temperature of the air flowing through the meter shall be sensed at a point on the downstream side of the meter at a distance recommended by the manufacturer but no further than five times the nominal pipe diameter.

6.3 Pressure measurement

Where a pressure tap is located on the meter body, it shall be used as a pressure sensing point during testing unless otherwise recommended by the manufacturer. In all other cases, pressure shall be measured as close as possible to the inlet of the meter.

6.4 Evaluation tests

6.4.1 Accuracy testing

6.4.1.1 At reference conditions, tests shall be performed at flow rates distributed over the measuring range with test mediums as specified in subsection 6.3 at working pressures as specified in subsection 6.1.1.1 (see Part 4, tables 2, 3 and 4).

6.4.1.2 At "other than reference" conditions, tests shall be performed with a flow rate of 0.25Qmax with test mediums as specified in subsection 6.3 at working pressures as specified in subsection 6.1.1.1 (see Part 4, Table 2, 3 and 4).

6.4.1.3 Where a meter is intended for medium and/or high operating pressure and is verified or reverified at the atmospheric pressure, tests for turbine meters intended for low operating pressure (as per Part 4, Table 2) shall be performed in addition to the applicable tests specified in 6.4.1.1 and 6.4.1.2 (see Part 4, tables 3 and 4).

Part 4, Table 2: Accuracy testing for turbine meters intended for low operating pressure
Test medium Working pressure (pw) Working temperature (tw) Environmental conditions Flow rate(Q)
Air Atmospheric Reference Reference Qmin ≤ Q ≤ Qmax
"Other than reference" "Other than reference" 0.25 Qmax
Part 4, Table 3: Accuracy testing for turbine meters intended for medium operating pressure
Test medium Working pressure (pw) Working temperature (tw) Environmental conditions Flow rate (Q)
Gas Pmin and Pmax Reference Reference Qmin ≤ Q ≤ Qmax
"Other than reference" "Other than reference" 0.25 Qmax
Part 4, Table 4: Accuracy testing for turbine meters intended for high operating pressure
Test medium Working pressure (pw) Working temperature (tw) Environmental conditions Flow rate (Q)
Gas 5000 kPa (720 psig) < pw Reference Reference Qmin ≤ Q ≤ Qmax
"Other than reference" "Other than reference" 0.25 Qmax
6.4.2 Swirl susceptibility testing

6.4.2.1 The requirements in Part 1, 12.5.7.4 shall apply unless otherwise stated in this section.

6.4.2.2 At reference conditions, tests shall be performed with flow rates at 0.25 Qmax, 0.4 Qmax and Qmax, with test mediums as specified in subsection 6.3 at working pressures as specified in subsection 6.1.1.1 (see Part 4, tables 5, 6 and 7).

6.4.2.3 Meters not meeting this performance requirement in the two recommended configurations judged most likely to produce inaccurate measurement shall not be considered for approval of type.

Part 4, Table 5: Swirl susceptibility testing for turbine meters intended for low operating pressure
Test medium Working pressure (pw) Working temperature (tw) Environmental conditions Flow rate(Q)
Air Atmospheric Reference Reference 0.25 Qmax, 0.4 Qmax and Qmax
Part 4, Table 6: Swirl susceptibility testing for turbine meters intended for medium operating pressure
Test medium Working pressure (pw) Working temperature (tw) Environmental conditions Flow rate (Q)
Gas Pmin and Pmax Reference Reference 0.25 Qmax, 0.4 Qmax and Qmax
Part 4, Table 7: Swirl susceptibility testing for turbine meters intended for high operating pressure
Test medium Working pressure (pw) Working temperature (tw) Environmental conditions Flow rate (Q)
Gas 5000 kPa (720 psig) < pw Reference Reference 0.25 Qmax, 0.4 Qmax and Qmax
6.4.3 Measuring cartridge interchangeability tests

Where the manufacturer claims that the measuring cartridge of the meter can be interchanged with different meter cases, the performance tests determined in 6.6.1.1 and subsection 6.6.2 shall be completed with:

  1. a different interchangeable measuring cartridge installed in a meter body; and
  2. an interchangeable measuring cartridge installed in different meter bodies.

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