DarcyWeisbach Pipe Friction Loss Calculator 
Compute Major Losses (Friction Loss) in Pipes using DarcyWeisbach Equation 

DarcyWeisbach calculation is mobiledevicefriendly as of July 11, 2014 Units in DarcyWeisbach calculator: ft=foot, m=meter, s=second. DarcyWeisbach Friction Loss Equation: D is called the "duct diameter" to keep the terminology general to include circular pipes and noncircular pipes, also known as ducts. For rectangular pipes (ducts), D=4A/P is known as the hydraulic diameter. More information about hydraulic diameter can be found on our noncircular to circular pipe conversion page. g = acceleration due to gravity = 32.174 ft/s^{2} = 9.806 m/s^{2}. Major loss (h_{f}) is the energy (or head) loss (expressed in length units  think of it as energy per unit weight of fluid) due to friction between the moving fluid and the duct. It is also known as friction loss. The DarcyWeisbach method is generally considered more accurate than the HazenWilliams method. Additionally, the DarcyWeisbach method is valid for any liquid or gas; HazenWilliams is only valid for water at ordinary temperatures (40 to 75 ^{o}F). The HazenWilliams method is very popular, especially among civil engineers, since its friction coefficient (C) is not a function of velocity or duct diameter. HazenWilliams is simpler than DarcyWeisbach for calculations where you are solving for flowrate, velocity, or diameter. More Discussion and References. The DarcyWeisbach calculation does not check for unreasonable inputs such as negative values. All values should be entered as positive.
© 19982014 LMNO Engineering, Research, and
Software, Ltd. All rights reserved. August 25, 2015: Made text fields show 8 significant figures rather than 16. Calculation still uses double precision internally.

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