The roughness is actually a measurement of all the asperities at the surface of a material, especially a pipe where it will oppose the flow of fluid. The following table is summarizing usual pipe roughness for many materials used for piping or ducts. 'Relative Roughness' or 'Roughness factor' of a pipe is the ratio of absolute roughness to the pipe diameter. Relative roughness factor is often used for pressure drop calculations for pipes and other equipment. The relative roughness factor is an important parameter for determining friction factor based on Reynold's number for flow in a pipe.

Commercial pipes comes in many different materials and many different sizes. The internal roughness of a pipe is an important factor when considering the friction losses of a fluid moving through the pipe.

Pipe and Duct Systems Table A.1 Average roughness of commercial pipes. Table A.6 Data for copper pipes Weight per Linear Foot of Gallons of Pipe and Water per Water (lb) Linear Foot Diameter (in.) Material Nominal Inner Outer Copper Type L 1/4 0.315 0.375 0.16 0.004. Aluminium, drawn/pressed: new: 0.0013 - 0.0015 mm: Aluminium, drawn/pressed: used: to 0.03 mm: Asbestos-cement: new, smooth: 0.03 - 0.1 mm: Brass, drawn/pressed. Absolute Roughness Coefficient - k - (10-3 m) (feet) Drawn Copper, Lead, Brass, Aluminum (new) and the like: 0.001 - 0.002 (3.28 - 6.56) 10-6: PVC, PE and other smooth Plastic Pipes: 0.0015 - 0.007 (0.49 - 2.30) 10-5: Stainless steel, bead blasted: 0.001 - 0.006 (0.00328 - 0.0197) 10-3: Stainless steel, turned: 0.0004 - 0.006 (0.00131 - 0.0197) 10-3.

For each pipe material either a single pipe roughness value or a range of roughness values is normally provided by the manufacturer. The roughness value, usually denoted as e, is used in the calculating the relative roughness of a pipe against the size of its diameter.

Absolute Roughness

The roughness of a pipe is normally specified in either mm or inches and common values range from 0.0015 mm for PVC pipes through to 3.0 mm for rough concrete pipes.

Relative Roughness

The relative roughness of a pipe is its roughness divided by its internal diameter or e/D, and this value is used in the calculation of the pipe friction factor, which is then used in the Darcy-Weisbach equation to calculate the friction loss in a pipe for a flowing fluid.

Pipe Materials and Common Pipe Roughness Values

Material	e (mm)	e (inches)
Concrete	0.3 - 3.0	0.012 - 0.12
Cast Iron	0.26	0.010
Galvanized Iron	0.15	0.006
Asphalted Cast Iron	0.12	0.0048
Commercial or Welded Steel	0.045	0.0018
PVC, Glass, Other Drawn Tubing	0.0015	0.00006

Pipe Materials and Pipe Diameter Database

Our Pipe Flow Expert software comes with its own database of pipe materials and pipe diameters, which includes the pipe roughness values and standard material schedules of many types of pipe. Users can also add their own pipe data for any material and any pipe size if required.

Pipe materials in the Pipe Flow Expert pipe database include Cast Iron (Class A,B and C), Copper Tube (Type X,Y,K,L,M), HDPE (SDR 7.3 to SDR 26), PVC (Schedule 40, 80, and CL100 to CL315), Stainless Steel (Schedule 5s, 10s, 40s), Steel (Schedule 40,80,160) and more.

Absolute Roughness Of Copper Pipe

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