Pipe Flow Expert is a software application for designing and analyzing complex pipe networks where the flows and pressures must be balanced to solve the system.

Flow and Pressure Loss Calculations produced by the Pipe Flow Expert software can be verified by comparison against published results from a number of well-known sources. 

The information in this document provides a general description of a published problem, the Reference Source, the Published Results Data, the Pipe Flow Expert Results Data and a commentary on the results obtained.

For each of the 50 cases detailed in this document, the Pipe Flow Expert Results Data compares well with the published results data. 


Friction Factors are calculated using the Colebrook-White equation.

Friction Loss for non-compressible fluids is calculated using the Darcy-Weisbach method, which provides accurate results for most fluids, including general process fluids. 

Gases: The ‘non-compressible’ Darcy-Weisbach equation also provides satisfactory results of reasonable accuracy for compressible fluids (gases) when the pressure drop in the system is less than 10% of the absolute pressure at the starting point. If the calculated pressure drop in the system is greater than 10% but less than 40% of the absolute pressure at the starting point then the Darcy-Weisbach equation will give reasonable accuracy provided that the calculations are repeated using the average density of the fluid (at the average pressure condition) in the pipeline.

Cases 37 to 41 in this document compare the Pipe Flow Expert results using its non-compressible calculation engine against published data for relatively low pressure loss gas systems, however Pipe Flow Expert now contains a separate Compressible calculation engine that allows for the solution of compressible systems with equations such as the General Fundamental Isothermal Flow equation, the Complete Isothermal equation, the AGA equation, the Panhandle A equation, the Panhandle B equation, and the IGT equation. There is a separate ‘Compressible Results Verification’ document that compares Pipe Flow Expert’s results using its compressible calculation engine against the published results of more than 25 compressible gas systems. 

Pipe Flow Expert is currently used by engineers in over 75 countries worldwide. 

We have clients in a variety of industries including aerospace, chemical processing, education, food and beverage, general engineering, mining, petrochemical, pharmaceutical, power generation, water and wastewater processing.