RUMUS KEHILANGAN TEKANAN PADA PIPA (HEADLOSS FORMULA)

Chezy-Manning Formula

HL =

where

HL = headloss in feet

Q = flow in cfs

L = pipe length in feet

d = pipe diameter in feet

n = Manning roughness coefficient

Darcy-Weisbach Formula

HL =

where:

HL = headloss (Length)

g = acceleration of gravity in(Length/Time/Time)

L = pipe length (Length)

d = pipe diameter (Length)

v = flow velocity (Length/Time)

f = friction factor (unitless)

The friction factor is a function of (e/d) and the Reynolds number, where e is a roughness

coefficient with units of length. The above formula can be used with any consistent set of

units.

Hazen-Williams Headloss Formula

HL =

where:

HL = headloss in feet

Q = flow in cfs

L = pipe length in feet

d = pipe diameter in feet

C = Roughness coefficient(Hazen-Williams C-factor)

Roughness Coefficients for New PipeHazen-Williams C Darcy-Weisbach Manning's n

(unitless) (millifeet) (unitless)Cast Iron 130 - 140 0.85 0.012 - 0.015Concrete or Concrete Lined 120 - 140 1.0 - 10 0.012 - 0.017Galvanized Iron 120 0.5 0.015 - 0.017Plastic 140 - 150 0.005 0.011 - 0.015Steel 140 - 150 0.15 0.015 - 0.017Vitrified Clay 110 0.013 - 0.015

Material