11 Some applications of copper-nickel alloys for ships’ hulls 19 12 Comparison between various specifications for 90/10 and 70/30 copper-nickel alloys 23 Figures Page 1 Corrosion rates of materials in flowing seawater 6 2 Cu-Ni-Fe diagram showing hot short areas 10 3 Roughness factors for copper-nickel alloys and steel 11. Pipe Roughness Coefficients Type of Piping Material “C” Factor Unlined Cast/Ductile Iron Pipe 100 Cement-Lined Cast/Ductile Iron Pipe 140 Steel Pipe (Dry Systems/Pre-action Systems) 100 Steel Pipe (Wet Systems/Deluge Systems) 120 Galvanized Steel Pipe 120 Plastic Tubing 150 Copper Tubing 150 Note 1: Unli ned c ast iron and unl ine d duc. Copper, brass, lead, tin or glass pipe or tubing 150/120 140 130 Wood Stave 145/110 120 110 Welded or Seamless Steel 150/80 130 100 Cast and ductile iron 150/80 130 100 Concrete 152/85 120 100 Corrugated steel - 60 60 Manning’s Equation roughness coefficient (n) Material Values for n Range Typical Design Value Polyethylene pipe 0.008-0.011 0. The absolute roughness of 0.0018″ is for aged pipe, but accepted in design practice because it is conservative. Flexible pipe is rougher than steel pipe, therefore, requires a larger diameter for the same maximum rate. For a flexible pipe, the roughness shall be given by ε = ID/250.0 unless alternative specification is given. The roughness may increase with use at a rate determined by the material.
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Please note that because of the variation in roughness in these materials depending on the source, the roughness values reported here have uncertainties ranging from ± 20 % for new wrought Iron to ± 70 % for riveted steel. A typical uncertainty in the roughness values can be assumed to be in the range ± − 30 -50 %.
This table lists the roughness Coefficients of Specific roughness, Hazen-Williams Coefficient and Manning Factor.
Specific Roughness | |||
---|---|---|---|
5 x 10-2 (1.6 x 10-4) | |||
4.6 x 10-2 (1.5 x 10-4) | |||
3.0 (1 x 10-2) | |||
2.0 (7 x 10-3) | |||
2 x 10-3 (7 x 10-6) | |||
Iron, Cast new | |||
Iron, Wrough, new | |||
Iron, Galvanized, new | |||
Iron, Asphalted, cast | |||
Brass, new | |||
Concrete, smoothed | |||
Concrete, Rough | |||
Rubber, Smoothed | |||
Wood, Stave | |||
Sources: Hydraulic Institute, Engineering Data Book. Various vendor data compiled by SAIC, 1998 F.M. White, Fluid Mechanics, 7th edition |
Surface Roughness for Various New Polyethylene Pipes (PE Pipes)
Values for New Pipe and Recommended Design Values Reported by Reference (2) | |
Riveted steel | |
Concrete | |
Wood stave | |
Cast Iron – Uncoated | |
Cast Iron – Coated | |
Galvanized Iron | |
Cast Iron – Asphalt Dipped | |
Commercial Steel or Wrought Iron | |
Drawn Tubing | |
Uncoated Steel | |
Coated Steel | |
Uncoated Asbestos – Cement | |
Cement Mortar Relined Pipes (Tate Process) | |
Smooth Pipes | |
PE and other thermoplastics, | |
Brass, Glass and Lead) |
Note: Pipes that have absolute roughness equal to or less than 0.000005 feet are considered to exhibit “smooth pipe” characteristics.
Roughness Coefficient Of Copper Pipe
Relative roughness and friction factors for new, clean pipes for flow of 60°F (15.6°C) water (Hydraulic Institute Engineering Data Book, Reference 5) (1 meter 39.37 in = 3.28 ft).
Where:
f = friction factor
D = Diameter (inches)
∈/ D = Relative Roughness
∈= MEasure of pipe wall roughness in feet (meters)
References:
Relative Roughness Of Copper Nickel Pipe
1. Swierzawski, Tadeusz J. (2000). Flow of Fluids, Chapter B8, Piping Handbook, 7th edition, Mohinder L. Nayyar, McGraw-Hill, New York, NY.
2. Lamont, Peter A. (1981, May). Common Pipe Flow Formulas Compared with the Theory of Roughness, Journal of the American Water Works Association, Denver, CO.
Related Resources:
Roughness Of Copper Pipe
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