Pipe Roughness
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.
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.
You can download Pipe Flow Expert for a free trial and see how it makes it easy to draw, design and calculate the flows and pressure drops in your pipe system.
