External Protection Systems On Steel Pipes

The steel shell is normally grit-blasted on the outside and inside according to the applicable standards as specified by the clients.

Over the years in the history of steel water supply pipelines, a wide variety of systems have been used to provide external corrosion protection for both above and below ground installations.

The most commonly used and effective external protection systems specified by clients in the water supply industry are as follows :

a) Below Ground / Buried Pipes
Hot Applied Bitumen Coating together with reinforced glass fiber tissues on primed external steel surface.

b) Above Ground / Exposed Pipes
Industrial paints such as Aluminium / zinc rich painting system, red-oxide and other epoxy coating system.

Other External Surface Protection Systems are as follows :
1) Reinforced coal tar enamel coating
2) Coal tar epoxy and other epoxy coating
3) Primer coating painting e.g. red lead oxide
4) Tape coating system

Internal Protection Systems On Steel Pipes

Cement mortar lining is one of the most commonly used methods to prevent internal corrosion of steel pipe while at the same time providing a smooth surface to maximise flow capacity.

This cement mortar lining is applied to the pipes by spinning in a centrifugal process producing a dense lining with a smooth surface. At the same time, excess water that migrates to the surface of the lining will be removed by skimming process. The high density, low void and water content results in a strong and low permeability cement mortar lining.

Either Ordinary Portland cement complying to BS 12 or Sulphate-Resistting Portland cement complying to BS 4027 and fine aggregate are mixed together to form the lining material.

Other Internal Surface Protection systems are also used as follows :
1) Centrifugal spun Bitumen lining
2) Centrifugal spun coal tar lining
3) Epoxy and coal tar epoxy lining
4) Painting system