FORMULAS

Frequently used formulas in pipeline construction;


1. h = f(LV2/2Dg)


h : Head loss (m)
L : Length of pipeline (m)
D: Diameter of pipe (m)
(Normally nominal diameter presented in meter is used.)
V: Flow velocity (m/s)
g : Acceleration of gravity (= 9.8 m/s2)
f : Head loss coefficient

2. For water pipeline, Hazen-Williams formula is commonly used.
V = 0.35464CH D0.63 I0.54
Q = 0.27853CH D2.63 I0.54

I = 10.666 CH-1.85 D-4.87 Q1.85 


Where, CH : Coefficient
For cement mortar or epoxy lined ductile iron pipe, a CH value of 150 can
be used; however for design purpose, 130 is recommended, which
includes losses in fittings, valves and other facilities, plus some
allowance.
I : Hydraulic gradient (unit head loss of the pipeline) = h/L
Q : Flow volume (m3/s)

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