Welcome ElectricalDesign HeatingDesign plus HVAC Welcome Installation Introducing, license Getting started Projects Reference Libraries References U-Value Calculator Common Absolute Pipe Roughness Absolute Pipe Roughness is usually defined for a material and can be measured experimentally. Following table gives typical roughness values in millimeters for commonly used piping materials. Surface Material Absolute Roughness Coefficient - ε in mm Aluminum, Lead 0.001 - 0.002 Drawn Brass, Drawn Copper 0.0015 Aluminum, Lead 0.001 - 0.002 PVC, Plastic Pipes 0.0015 Fiberglass 0.005 Stainless steel 0.015 Steel commercial pipe 0.045 - 0.09 Stretched steel 0.015 Weld steel 0.045 Galvanized steel 0.15 Rusted steel 0.15 - 4 Riveted steel 0.9 - 9 New cast iron 0.25 - 0.8 Worn cast iron 0.8 - 1.5 Corroding cast iron 1.5 - 2.5 Asphalted cast iron 0.012 Galvanized iron 0.015 Smoothed cement 0.3 Ordinary concrete 0.3 - 3 Well planed wood 0.18 - 0.9 Ordinary wood 5