Fittings Loss Coefficients

Resistance coefficients for common pipe fittings and valves. Includes Crane TP-410 K values, Hooper 2K, and Darby 3K correlations.

Crane TP-410 K

Crane TP-410 - Resistance Coefficients K = f_T * (L/D)_eq · Values are K at fully-turbulent flow. f_T is the fully-turbulent Darcy f for commercial steel pipe at the fitting size.

Fitting / Valve	(L/D)_eq	K (for 4in std pipe, f_T=0.017)	Notes
Gate valve, full open	8	0.14	ball/plug valves similar
Globe valve, full open	340	5.8	straight through pattern
Angle valve, full open	55	0.94
Y-pattern globe valve	55	0.94
Plug valve, straight through	18	0.31
Butterfly valve, 2-8in	45	0.77	larger sizes see TP-410
Check valve, lift	600	10.2	min velocity to lift required
Check valve, swing	50	0.85
Foot valve, poppet disc	420	7.1	strainer basket
90 deg elbow, standard (r/D=1)	30	0.51	flanged or threaded
90 deg elbow, long radius (r/D=1.5)	16	0.27
90 deg elbow, r/D=2	12	0.2
45 deg elbow, standard	16	0.27
Return bend (180 deg), r/D=1.5	50	0.85
Tee, line flow (thru run)	20	0.34
Tee, branch flow	60	1.02	used as 90 deg
Coupling / union	0	0.04	negligible
Pipe entrance, flush	0	0.5	K = 0.5
Pipe entrance, rounded (r/D>=0.15)	0	0.04
Pipe entrance, projecting (Borda)	0	1
Pipe exit, into large tank	0	1	K = 1.0 always
Sudden contraction (A2/A1 -> 0)	0	0.5	see TP-410 App A
Sudden expansion (A1/A2 -> 0)	0	1
Source: Crane Co., 'Flow of Fluids Through Valves, Fittings and Pipe', Technical Paper 410, 2013 ed., Appendix A, pp. A-27 to A-29.

Hooper 2K

Hooper 2K Method (Hooper, Chem Eng, 1981) · K = K1/Re + Kinf * (1 + 1/Dn), Dn in inches

Fitting	K1	Kinf	Notes
Elbow 90, standard threaded (r/D=1)	800	0.4
Elbow 90, flanged/welded standard (r/D=1)	800	0.25
Elbow 90, long radius (r/D=1.5)	800	0.2
Elbow 90, mitered (1 weld, 90 deg)	1000	1.15
Elbow 90, mitered (2 welds, 45 deg each)	800	0.35
Elbow 45, standard (r/D=1)	500	0.2
Elbow 45, long radius (r/D=1.5)	500	0.15
Elbow 45, mitered (1 weld)	500	0.25
Elbow 180, standard (r/D=1) all types	1000	0.6
Elbow 180, long radius (r/D=1.5) all types	1000	0.35
Tee, used as elbow, standard	500	0.7	through branch
Tee, used as elbow, long radius	800	0.4
Tee, run-through, threaded	200	0.1
Tee, run-through, flanged/welded	150	0.05
Gate valve, full open	300	0.1
Ball valve, full open	300	0.1
Plug valve, full open, straight-thru	300	0.1
Globe valve, standard, full open	1500	4
Globe valve, angle or Y-pattern	1000	2
Diaphragm valve, dam type	1000	2
Butterfly valve	800	0.25
Check valve, lift	2000	10
Check valve, swing	1500	1.5
Check valve, tilting-disc	1000	0.5
Source: Hooper, W.B., Chemical Engineering, Aug 24, 1981, pp. 96-100; reproduced Perry's 9th Ed., Table 6-5.

Darby 3K

Darby 3K Method (Darby, Chem Eng, 1999) · K = Km/Re + Ki * (1 + Kd / Dn^0.3), Dn in inches

Fitting	Km	Ki	Kd	Notes
Elbow 90, threaded, standard (r/D=1)	800	0.14	4
Elbow 90, flanged/welded, standard (r/D=1)	800	0.071	4.2
Elbow 90, long radius (r/D=1.5), all types	800	0.091	4
Elbow 90, mitered, 1 weld (90 deg)	1000	0.27	4
Elbow 90, mitered, 2 welds (45 deg each)	800	0.068	4.1
Elbow 90, mitered, 3 welds (30 deg each)	800	0.035	4.2
Elbow 45, standard (r/D=1), all types	500	0.071	4.2
Elbow 45, long radius (r/D=1.5)	500	0.052	4
Elbow 45, mitered, 1 weld	500	0.086	4
Elbow 45, mitered, 2 welds	500	0.052	4
Elbow 180, threaded, standard (r/D=1)	1000	0.23	4
Elbow 180, flanged/welded, standard	1000	0.12	4
Elbow 180, long radius (r/D=1.5), all types	1000	0.1	4
Tee, through branch, threaded, standard	500	0.274	4	as elbow
Tee, through branch, flanged/welded	800	0.14	4
Tee, through branch, long radius	800	0.28	4
Tee, run-through, threaded, standard	200	0.091	4
Tee, run-through, flanged/welded	150	0.05	4
Tee, run-through, stub-in branch	100	0	0
Valve, gate, full open	300	0.037	3.9
Valve, ball, full open	300	0.017	3.5
Valve, plug, straight-through	300	0.018	3.9
Valve, plug, 3-way (flow thru)	300	0.082	4
Valve, plug, 3-way (branch)	500	0.18	4
Valve, globe, standard	1500	1.7	3.6
Valve, globe, angle or Y	1000	0.7	4
Valve, diaphragm, dam type	1000	0.69	4.9
Valve, butterfly	800	0.091	4
Check valve, lift	2000	2.85	3.8
Check valve, swing	1500	0.46	4
Check valve, tilting-disc	1000	0.267	4
Source: Darby, R., Chemical Engineering, July 1999, pp. 101-104; Darby, Chemical Engineering Fluid Mechanics, 2nd Ed., Marcel Dekker 2001, Table 7-3.

Source: fittings_loss_coefficients_v1.xlsx

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