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Normalized to Actual

When sizing & specifying instruments for gas flow measurement, such as Thermal Mass Flowmeters, Variable Area Flowmeters, or Vortex Flowmeters, actual flows must be converted to normalized flows (or Standard flow) in order to determine if a gas flow meter can be specified for a given application.  This conversion is performed using the ideal gas law.  Gas flow meter users need a reference condition to compare different flows existing at different flowing conditions of pressure and temperature. However, the problem with Normal or Standard conditions is that there are several different pressure and temperature references depending upon whom you talk to.  SmartmeasurementTM’s user friendly normalized to actual or actual to normalized calculators allows our customers the flexibility to use their own reference conditions to come up with the correct answer.  These calculations are frequently used for gas flow measurement applications as a slight change in temperature and/or pressure affects the fluid density.  Please make sure that whatever flows you are comparing, you are using the same reference pressure and temperature conditions.  A good analogy for this type of calculation is exchange rates for the various currencies used around the world, where the conversions are referenced to either the US dollar or the Euro.

If you have a gas flow measurement application, please feel free to contact SmartMeasurementTM’s U.S. offices at 1-866-404-5415 for assistance. Our team of application engineers would be happy to review your application and quote a suitable flow measurement technology at industry-leading prices.


Normalized Flow Rate, QN 
Atmospheric Pressure, Patm 
Gage Pressure, Pg 
Temperature, T 


Actual flow rate Qg =  1.07322

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