InfoWater Pro Help Documentation infowaterpro

Minor losses (also called local losses) are caused by the added turbulence that occurs at bends and fittings. The importance of including such losses will depend on the layout of the pipe network and the degree of accuracy required. In water distribution systems, minor losses are typically small compared to pipe friction losses. However, these losses can be significant in heating and cooling systems. InfoWater allows each pipe and valve to have a minor loss coefficient associated with it. It computes the resulting headloss from the following formula:

Where hL is the headloss in feet, K is a minor loss coefficient, q is flow rate in cfs, and d is diameter in ft. The following table provides values for loss coefficient, K, for several kinds of components.

ComponentLoss Coefficient
Globe valve, fully open10.0
Angle valve, fully open5.0
Swing check valve, fully open2.5
Gate valve, fully open0.2
Butterfly valve, fully open0.3
Diaphragm valve, fully open2.3
Short-radius elbow0.9
Medium-radius elbow0.8
Long-radius elbow0.6
Standard tee, 90o Turn1.8
45° elbow0.4
Closed return bend2.2
Standard tee - flow through run0.6
Standard tee - flow through branch1.8
Square entrance0.5

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