Before revision: Typical C factors used in design, which take into account some increase in roughness as pipe ages are as follows: Material C Factor low C Factor high Reference Asbestos-cement 140 140 - Cast iron new 130 130 Cast iron 10 years 107 113 Cast iron 20 years 89 100 Cast iron 30 years 75 90 Cast iron 40 years 64 83 Cement-Mortar Lined Ductile Iron Pipe 140 140 – Concrete 100 140 Copper 130 140 Steel 90 110 – Galvanized iron 120 120 Polyethylene 140 140 Polyvinyl chloride (PVC) 150 150 Fibre-reinforced plastic (FRP) 150 150 Pipe equation The general form can be specialized for full pipe flows.
After revision: Typical C factors used in design, which take into account some increase in roughness as pipe ages are as follows: Material C Factor low C Factor high Reference Asbestos-cement 140 140 - Cast iron new 130 130 Cast iron 10 years 107 113 Cast iron 20 years 8ET"/> Cement-Mortar Lined Ductile Iron Pipe 140 140 – Concrete 100 140 Copper 130 140 Steel 90 110 – Galvanized iron 120 120 Polyethylene 140 140 Polyvinyl chloride (PVC) 150 150 Fibre-reinforced plastic (FRP) 150 150 Pipe equation The general form can be specialized for full pipe flows.