the ENGINEERING page
Typical surface roughness
| Material | Nature of Material | Roughness [mm] |
| Steel pipe | drawn, new | 0.02 - 0.1 |
| welded, new | 0.05 - 0.1 | |
| galvanized, new | 0.15 | |
| used, cleaned | 0.15 - 0.2 | |
| lightly corroded | 0.1 - 0.4 | |
| severely corroded | 0.4 - 3 | |
| light scaling | 1 - 1.5 | |
| heavy scaling | 1.5 - 4 | |
| bitumed coated | 0.05 | |
| cast - iron pipe | new | 0.25 - 1 |
| corroded | 1 - 2 | |
| with scaling | 1 - 4 | |
| concrete pipe | smooth finish | 0.3 - 1 |
| rough | 1 - 3 | |
| Sheet steel | smooth | 0.07 |
| Glass, lead, copper, brass | 0.0001 - 0.0015 |