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Turbine meters

At our patented facility,  we’re able to test flow meters over a wide range of operating conditions using carbon dioxide (CO2) matched to true operating conditions.  For high pressure testing, we match the Reynolds Number using the gas density of CO2 to that of Natural Gas in field conditions.

Calibration capabilities​
Flow range 350 - 230,000 ACFH (10 - 6,500 m3/hr)
Pressure range
(CO2 test medium)
2" - 12" turbine meter
0 - 235 psig (0 - 1,620 kPa)
Equivalent pressure 610 psig natural gas, based on flow rate and density
Temperature range 5°C - 35°C (41°F - 95°F)
Fluid type CO2 
ANSI rating & size ANSI 150, 300, 600 and meters sized
NPS 2 to NPS 12
Maximum reynolds number 9,200,000
Measurement uncertainty +/- 0.27%
Reproducibility +/-0.2%
Traceability Traceable to international standards through NMI
(Holland Metrology N.V.)
Meter Runs Complete meter runs up to 22' (6.7m) by special arrangement

A significant reduction in the margin of error

The dependency of turbine meters on Reynolds Numbers can have a severe impact on measurement accuracy. The key is to replicate actual operating conditions. Results obtained with traditional tests rely on air at atmospheric pressure. As a result, some measurements, and consequently calibration, are inherently inaccurate. By utilizing carbon dioxide (CO2) at high pressures – in effect duplicating a range of true operating conditions – our high pressure testing process can significantly reduce the margin of error.
Studies have shown that turbine meters need to be calibrated under in-service conditions for acceptable accuracy.  The best calibration results are obtained by matching the in-service Reynolds Numbers and flow rates to the meter under test.  For a true representation of how a meter will operate in the field it is recommended that it be tested at a higher pressure than atmospheric if is being used at higher pressures in the field.
Meters in low-pressure, low-flow applications operate at the lowest Reynolds conditions.  Meter performance can change up to several percent when comparing low pressure test conditions (typically under 1-1.5 million Reynolds Numbers) to high pressure test conditions. Meters that are tested at lower flows relative to the meters Qmax (maximum pressure) and lower pressures (eg. Atmospheric) have the greatest loss in accuracy.  Meters that operate at a higher Reynolds Number and tested at high pressure provide a more accurate calibration.

A significant benefit to both utilities and their customers

High Pressure Testing significantly advances industrial metering for gas utilities across North America and offers improvements to the accuracy of turbine meter testing with these benefits:

  • Flexibility to change pressure and temperature in order to meet your company standards
  • certified repair facility for Sensus and Instromet meters with extensive experience in Elster and Daniel products
  • completion of all shipping and customs documentation to reduce delays and keep your admin time low
  • large volume of spare parts kept on hand to reduce waiting time
  • all tests can be remotely witnessed
  • more accurate billing for turbine customers
  • established credibility through third party verification
  • immediate access, year round, to accurate test facilities
  • faster turnaround times
  • technical expertise

What is Reynolds Number?

Reynolds Number is a dimensionless ratio of inertial to viscous forces that takes into account the flow rate and physical properties of a fluid.  It is proportional to flow rate and density and inversely proportional to meter diameter and viscosity.
What does the industry recommend?

AGA (American Gas Association)
The current edition of the Report No 7 (February 2006), Measurement of Natural Gas by Turbine Meter recommends that:

  • a meter calibration carried out in a test facility over a particular range of Reynolds numbers characterize the meter’s performance when used to measure gas over the same range of Reynolds number when the meter is in service. (section
  • the expected operating Reynolds number range and/or density for a meter needs to be taken into account when designing a calibration program. (section 6.3.2)

ERCB (Energy Resources Conservation Board which regulates the oil and gas industry in Alberta) recommends in Directive 17,, item 4 that meters with moving parts be proved “….at a pressure that is within the normal operating condition for that meter location.”
CEN (European Committee for Standardization)
The Europeans have a similar requirement for testing turbine meters. In the CEN document EN 12261-2002 section, it is recommended that:

  • for a meter type specified for measurement in a pressure range below or equal to 4 bar the error of indication test shall be carried out with a gas at atmospheric conditions (± 100 mbar)
  • for a meter type specified for measurement in a pressure range extended above 4 bar the error of indication test shall be carried out with a gas in the range of the specified metering conditions. The tests shall be carried out at least at the lowest and the highest working pressure specified by the manufacturer. However, for specified maximum pressures above 50 bar a test at 50 bar is deemed acceptable.

Remote testing witnessing

Customers can view their meter being tested remotely from anywhere in the world.  For high pressure testing services on your turbine meter that require witnessing, this service will save you time, travel and expense costs.  To arrange this service, please contact us to set this up. A time will be arranged for you to log in with an ID and password.
Once your remote witnessing of a test is arranged, you will receive an email a few days before with the test schedule, website address and log in information.