Both the high-density polyethylene and polypropylene three-layer coating systems have low water permeation characteristics for improved isolation from the surrounding sea water.
External Anti-corrosion Protection Systems
Tenaris offers external anti-corrosion protection systems for offshore pipe in the form of Fusion Bonded Epoxy (FBE) and three-layer polyethylene/polypropylene external pipe coating systems in alliance with international coating companies.
Fusion Bonded Epoxy Coating System
The Fusion Bonded Epoxy (FBE) coating system is an externally-applied thermosetting resin for pipe. It is applied in the form of a dry powder at thicknesses of 400-600 microns onto the heated surface of the steel pipe. Once applied and cured, the epoxy film exhibits an extremely hard surface with excellent adhesion to the steel surface. The FBE protective surface is homogeneous and offers an excellent resistance to chemical reaction.
The FBE coating systems provide protection at moderate temperatures (-40ºC to 85ºC) and come in two options:
- FBE Dual: recommended for sub-sea pipelines and flowlines operating in the toughest environments. It offers excellent impact resistance and abrasion properties which, combined with its good flexibility, provide suitable protection against coating damage during pipe transportation and construction
- FBE Non-slip: this coating system provides a rough, non-slip surface for a pipeline that will subsequently be concrete-coated
Three-Layer Coating Systems: Polyethylene AND Polypropylene
The three-layer pipe external anti-corrosion system consists of a layer of high-performance Fusion Bonded Epoxy onto which a co-polymer adhesive layer is extruded, followed by a layer of extruded polyethylene or polypropylene until the desired thickness is obtained.
This coating system provide pipeline protection at the following operating temperatures:
- Three-layer polyethylene: suitable for temperatures between -40ºC and 85ºC
- Three-layer polypropylene: suitable for temperatures between -40ºC and 110ºC
In addition to the chemical and adhesive properties of the epoxy powder, the polyethylene coating system provides physical and mechanical advantages. The polypropylene coating system ensures performance at high temperatures.
Advantages OF THE Three-Layer Coating System
- Excellent corrosion resistance. When exposed to either acid or alkaline media, an extended lifetime in highly corrosive soils is assured
- Strong steel adhesion: 20 times more adhesive than traditional plastic tape systems
- Excellent cathodic disbondment test results
- Excellent mechanical resistance
- Free of holidays: The hot extrusion method used to perform the coating assures a continuous and a uniform thickness profile, without air bubbles and holiday-free
- High dielectric resistance
- Superior bending ability for pipe laying applications
- High impermeability: Both the high-density polyethylene and polypropylene have low water permeation characteristics that allow improved isolation from the surrounding sea water compared to other coating systems