## Losses in Valves, Fittings, and Bends

### Figure 1 – Typical Resistance Coefficients for Valves and Fittings [1],[2]

Rotodynamic Pumps for Pump Piping

ANSI/HI 9.6.6 details pump piping requirements for rotodynamic pumps and effects of inlet/outlet piping on pump performance. This standard is applicable to all piping downstream and upstream from the pump but not when entering tank, vessel or intake structure. This document is intended to complement ANSI/HI 9.8 Intake Design for Rotodynamic Pumps.

Fitting | Fitting Type | Range of Variation | ||||||||
---|---|---|---|---|---|---|---|---|---|---|

90 Deg. Elbow | Regular Screwed | ± 20 percent above 2 inch size | ||||||||

Regular Screwed | ± 40 percent above 2 inch size | |||||||||

Long Radius, Screwed | ± 25 percent | |||||||||

Regular Flanged | ± 35 percent | |||||||||

Long Radius, Flanged | ± 30percent | |||||||||

45 Deg. Elbow | Regular Screwed | ± 10 percent | ||||||||

Long Radius, Flanged | ± 10 percent | |||||||||

180 Deg. Bend | Regular Screwed | ± 25percent | ||||||||

Regular Flanged | ± 35 percent | |||||||||

Long Radius, Flanged | ± 30 percent | |||||||||

Tee | Screwed, Line or Branch Flow | ± 25percent | ||||||||

Flanged, Line or Branch Flow | ± 35percent | |||||||||

Globe Valve | Screwed | ± 25percent | ||||||||

Flanged | ± 25percent | |||||||||

Fitting | Fitting Type | Range of Variation | ||||||||

Gate Valve | Screwed | ± 25percent | ||||||||

Flanged | ± 50 percent | |||||||||

Check Valve | Screwed | ± 30 percent | ||||||||

Flanged | + 200 percent, - 80 percent | |||||||||

Sleeve Check Valve | Multiply flanged values by 0.2 to 0.5 | |||||||||

Tilting Check Valve | Multiply flanged values by 0.13 to 0.19 | |||||||||

Drainage Gate Check | Multiply flanged values by 0.03 to 0.07 | |||||||||

Angle Valve | Screwed | ± 20 percent | ||||||||

Flanged | ± 50 percent | |||||||||

Basket Strainer | ± 50 percent | |||||||||

Foot Valve | ± 50 percent | |||||||||

Couplings | ± 50 percent | |||||||||

Unions | ± 50 percent | |||||||||

Reducers | ± 50 percent |

Fitting | Fitting Type | Range of Variation | ||||||||
---|---|---|---|---|---|---|---|---|---|---|

90 Deg. Elbow | Regular Screwed | ± 20 percent above 2 inch size | ||||||||

Regular Screwed | ± 40 percent above 2 inch size | |||||||||

Long Radius, Screwed | ± 25 percent | |||||||||

Regular Flanged | ± 35 percent | |||||||||

Long Radius, Flanged | ± 30percent | |||||||||

45 Deg. Elbow | Regular Screwed | ± 10 percent | ||||||||

Long Radius, Flanged | ± 10 percent | |||||||||

180 Deg. Bend | Regular Screwed | ± 25percent | ||||||||

Regular Flanged | ± 35 percent | |||||||||

Long Radius, Flanged | ± 30 percent | |||||||||

Tee | Screwed, Line or Branch Flow | ± 25percent | ||||||||

Flanged, Line or Branch Flow | ± 35percent | |||||||||

Globe Valve | Screwed | ± 25percent | ||||||||

Flanged | ± 25percent | |||||||||

Fitting | Fitting Type | Range of Variation | ||||||||

Gate Valve | Screwed | ± 25percent | ||||||||

Flanged | ± 50 percent | |||||||||

Check Valve | Screwed | ± 30 percent | ||||||||

Flanged | + 200 percent, - 80 percent | |||||||||

Sleeve Check Valve | Multiply flanged values by 0.2 to 0.5 | |||||||||

Tilting Check Valve | Multiply flanged values by 0.13 to 0.19 | |||||||||

Drainage Gate Check | Multiply flanged values by 0.03 to 0.07 | |||||||||

Angle Valve | Screwed | ± 20 percent | ||||||||

Flanged | ± 50 percent | |||||||||

Basket Strainer | ± 50 percent | |||||||||

Foot Valve | ± 50 percent | |||||||||

Couplings | ± 50 percent | |||||||||

Unions | ± 50 percent | |||||||||

Reducers | ± 50 percent |

- The value of D given in the charts is nominal IPS (Iron Pipe Size).

### Figure 2 – Resistance Coefficients for Miter Bends at Reynolds Number ≈ 2.25 x 10^{5} [3]

K_{s} = RESISTANCE COEFFICIENT FOR SMOOTH SURFACE

K_{r} = RESISTANCE COEFFICIENT FOR ROUGH SURFACE, ε/D = 0.0022

### Figure 3 – Resistance Coefficients for 90 Degree Bends of Uniform Diameter [4]

### Figure 4 – Resistance Coefficients for 90 Degree Bends of Uniform Diameter and Smooth Surface at Reynolds Number ≈ 2.25 x 10^{5} [5]

### References

- Hydraulic Institute, Engineering Data Book, Second Edition, 1990, Table 32a.
- Hydraulic Institute, Engineering Data Book, Second Edition, 1990, Table 32b.
- Hydraulic Institute, Engineering Data Book, Second Edition, 1990, Table 33.
- Hydraulic Institute, Engineering Data Book, Second Edition, 1990, Figure IIB-5A.
- Hydraulic Institute, Engineering Data Book, Second Edition, 1990, Figure IIB-5B.

Last updated on May 12th, 2020