Loss coefficient for different pipe fittings

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

h_{minor_loss} = ξ v²/ 2 g         (1)

where

h_{minor_loss} = minor head loss (m, ft)

ξ = minor loss coefficient

v = flow velocity (m/s, ft/s)

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

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

Type of Component or Fitting	Minor Loss Coefficient - ξ -
Tee, Flanged, Line Flow	0.2
Tee, Threaded, Line Flow	0.9
Tee, Flanged, Branched Flow	1.0
Tee, Threaded , 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