• For steel pipes, the value for c is to be in accordance with 4-6-2/Table 3.
• For non-ferrous metal pipes (excluding copper-nickel alloys containing 10% or more nickel), c = 0.8 mm (0.03 in.).
• For copper-nickel alloys containing 10% or more nickel, c = 0.5 mm (0.02 in.).
• Where the pipe material is corrosion resistant with respect to the media, e.g., special alloy steel, c = 0.