Minor Loss Coefficients in Pipes and Tubes Components

Minor loss coefficients for common used components in pipe and tube systems

Minor head loss in pipe and tube systems can be expressed as

hminor_loss = ξ v2/ (2 g)                             (1)


hminor_loss = minor head loss (m, ft)

ξ = minor loss coefficient

v = flow velocity (m/s, ft/s)

g = acceleration of gravity (9.81 m/s2, 32.17 ft/s2)

Minor loss coefficients for some of the most common used components in pipe and tube systems

Type of Component or FittingMinor Loss Coefficient
- ξ -
Tee, Flanged, Dividing Line Flow 0.2
Tee, Threaded, Dividing Line Flow 0.9
Tee, Flanged, Dividing Branched Flow 1.0
Tee, Threaded , Dividing Branch Flow 2.0
Union, Threaded 0.08
Elbow, Flanged Regular 90o 0.3
Elbow, Threaded Regular 90o 1.5
Elbow, Threaded Regular 45o 0.4
Elbow, Flanged Long Radius 90o 0.2
Elbow, Threaded Long Radius 90o 0.7
Elbow, Flanged Long Radius 45o 0.2
Return Bend, Flanged 180o 0.2
Return Bend, Threaded 180o 1.5
Globe Valve, Fully Open 10
Angle Valve, Fully Open 2
Gate Valve, Fully Open 0.15
Gate Valve, 1/4 Closed 0.26
Gate Valve, 1/2 Closed 2.1
Gate Valve, 3/4 Closed 17
Swing Check Valve, Forward Flow 2
Ball Valve, Fully Open 0.05
Ball Valve, 1/3 Closed 5.5
Ball Valve, 2/3 Closed 200
Diaphragm Valve, Open 2.3
Diaphragm Valve, Half Open 4.3
Diaphragm Valve, 1/4 Open 21
Water meter 7

Example - Minor Loss in a Ball Valve 1/3 Closed

The minor loss in a ball valve with flow velocity 2 m/s can be calculated

hminor_loss = (5.5) (2 m/s)2/ (2 (9.81 m/s2))

                 = 1.1 m

Related Topics

  • Fluid Mechanics - The study of fluids - liquids and gases. Involves velocity, pressure, density and temperature as functions of space and time
  • Fluid Flow and Pressure Drop - Pipe lines - fluid flow and pressure loss - water, sewer, steel pipes, pvc pipes, copper tubes and more

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