CORROSION PROTECTION FOR STEEL PIPES
Prior to corrosion protection system to be applied, the surface of the steel pipes shall be clean and free from scale, loose rust, oil, grease or other foreign matter.
The surface shall be cleaned as per quality of surface finish specified in BS 4232, BS 7079 or Swedish Standard SIS 05-5900 or any other applicable standard as specified.
External Corrosion Protection System
External Surface Protection Systems for Steel Pipes and Fittings are:
a) Bitumen Sheathing
The pipes and fittings shall be covered with a layer of sheathing material, applied as a hot coating or mastic to provide a seamless, consolidated and smooth layer. The sheathing material shall consist of natural or blown petroleum bitumen mixed with an inert filler.
b) Reinforced Bitumen Sheathing
Bitumen Sheathing with the addition of an overlapping spiral wrapping of woven glass cloth firmly embedded in the sheathing.
c) Bitumen Enamel Wrapping
Bitumen shall be complying to Type 2 of BS EN 10300 or BS 4147 and inner wrapping of glass tissue and an outer wrapping of bitumen impregnated reinforced glass tissue. The wrapping materials shall be spirally wound onto the pipes and specials simultaneously with the bitumen coating.
d) Reinforced Bitumen Enamel Wrapping
Same as Bitumen enamel wrapping except the outer wrapping shall be of composite glass fibre fabric.
e) Painting
- Organic and Inorganic Zinc Rich Coating
- Epoxy Coatings such as Glassflake, Mastic Epoxy and Coal Tar Epoxy
- 100% Solid Polyurethane (PU)
Internal Corrosion Protection System
Internal Surface Protection Systems for Steel Pipes and Fittings are:
b) Centrifugally Spun Concrete Lining
The lining shall be concrete made from mixing Ordinary Portland Cement or from Sulphate – resisting Portland Cement, clean fine aggregate and water. The concrete shall then be applied centrifugally to the entire inner surface of the pipes except at the cut back reserved for field jointing.
a) Centrifugally Spun Bitumen Lining
The lining material consists of a uniform blend of natural or blown bitumen mixed with an inert filler to produre a homogeneous composition. The lining materials shall be applied centrifugally to straight pipe while in a hot fluid condition.
d) Painting
- Organic and Inorganic Zinc Rich Coating
- Epoxy Coatings such as Glassflake, Mastic Epoxy and Coal Tar Epoxy
- 100% Solid Polyurethane (PU)
c) Centrifugally Spun Cement Lining
The lining shall be cement mortar made from mixing Ordinary Portland Cement or from Sulphate- resisting Portland Cement, mixed with specially graded washed Silica Sand and water. The cement mortar shall then be applied centrifugally to the entire inner surface of the pipes except at the cut back reserved for field jointing.
