Copper pipes are widely used for handling fresh and drinking water and generally they perform well and last for many years. However, occasionally there are leaks, and one cause of failure is erosion corrosion. This is caused when the water flow is so turbulent that it destroys the protective film on the metal surface, which then corrodes and forms the film again, which is again destroyed, and so on.

There are recommendations for safe velocities with copper tubes in fresh waters, but these can depend on water temperature. A UK recommendation is a maximum velocity of 1.0m/s in hot water (50 to 60°C), which can be increased to 2.0m/s in cold water (10 – 20°C. However, the turbulence can be greatly increased after sharp bends, and if these are present it is prudent to reduce the flow velocity. The alternative is to use large radius bends to minimise the turbulence.
 

Erosion corrosion of copper pipe after sharp bend.