Coated Pipe

Coated Pipe

The coated pipe is a group of metal pipes with anti-corrosion coatings. These coatings are commonly utilized to preserve the steel pipe used in the building of pipelines, reinforcing steel, and a broad variety of piping connections. This protective coating helps prevent corrosion, which can cause leaks, disruptions in operation, and even explosions of the steel wall.

Pipeline coating is a cost-effective and practical option for preserving the integrity of pipelines. It is widely regarded as one of the most dependable corrosion prevention technologies utilized by businesses worldwide today. However, pipeline coating is not an easy operation; it necessitates a lengthy process to complete a successful pipe painting mission.

Oil and gas coated pipes can be classified into two types, each with its own set of unique and stringent requirements: internal coated pipes and external coated pipes.


Executive Standard of Coated pipes

  • API RP 5L2
  • ISO 15741
  • AWWA C210
  • SY/T 6717
  • DEP

Internal coated Pipe

Internal pipeline coatings must be constructed to withstand the high impact caused by these fast-moving particulates. Solid particles in oil and gas fluids include sodium chloride, potassium chloride, other salts, carbonates, and sulfates, partially polymerized oils such as waxes and paraffin, as well as silica, dirt, and greases. Some of the particles disintegrate in the fluid, while others remain suspended. These particulates become fiercely corrosive missiles when they travel through pipes at speeds nearing 200 mph. 

the flow chart shows the process of internal coated pipe

TYPES OF Internal coated pipes

For steel potable water transmission coated pipe, there are five common types of interior coating or lining material. Coal tar enamel, cement mortar, liquid-applied epoxy, fusion-bonded epoxy (FBE), and polyurethane are among the materials on the list (PU). Each of these lining technologies has advantages and disadvantages. Furthermore, each interior coating type has surface preparation and application requirements.

- Coal Tar Enamel

The coal tar pitch, which serves as the foundation for coal tar enamel (CTE), is composed of stable molecules generated during coking processes at around 1,300°C. The fillers and coal increase the product’s flexibility and strength. The robust molecular arrangement provides CTE with the properties required to protect pipelines from corrosion.

- Cement Mortar

Cement mortar linings provide long-term protection at a low cost and remain one of the standard linings for potable water pipes. A major benefit of cement mortar is the ease of application.

- Liquid Applied Epoxy

Cement mortar linings offer long-term protection at a reasonable cost and are still used as a typical lining for potable water pipelines. The simplicity of application is a significant advantage of cement mortar.

- Fusion Bonded Epoxies

Fusion bonded epoxies are a one-part, thermosetting, heat-curable epoxy. FBE is applied to heated parts in the form of a powder (10-40 mils) that quickly gels from liquid to solid, has great adherence to the steel surface, and is a very robust coating that resists damage during handling.

- Polyurethane

Aromatic polyurethanes are 100 percent solid materials with no VOCs. Polyurethane linings are normally applied with a minimum thickness of 20 mils; however, thicker lining applications are conceivable.

External coated Pipe

Coated pipelines for the oil and gas industry can be located all over the world. Pipelines can be installed above ground, underground, or immersed in fresh or saltwater. External pipeline coatings must be built to resist such a wide range of climatic conditions. Soil stress, soil-borne pollutants, and saltwater all pose significant difficulties to the performance of external pipeline coatings. External coatings must also be resistant to indigenous bacteria, other flora, wastewater, and the chemicals and solvents used in hydrocarbon processing. Pipelines can be found in the hot desert, where temperatures frequently surpass 100°F, and in Alaska, where temperatures can drop below -76°F. Subsurface conditions in permafrost zones, where ground temperatures rarely surpass 32°F, make subterranean pipe construction challenging and virtually always necessitate above-ground pipeline installations.

this flow chart shows the process of manufacturing external coated pipe

TYPES OF External coated Pipes

- FBE Coated Pipe

The Fusion Bonded Epoxy (FBE) coating prevents corrosion on pipe surfaces. Double or triple layers of FBE may even improve friction and abrasion resistance. In 3-layer PE/PP coating systems, FBE coating is also employed as the priming layer.

At temperatures ranging from 220 to 235°C, the electrostatic epoxy powder is sprayed onto a pipe. When the epoxy powder reaches the hot pipe surface, it melts and forms a uniform layer of epoxy coating on the pipe.

- Dual Layer FBE Coated Pipe

Dual-layer FBE is used for a variety of service applications, including directional drilling, anti-abrasion for road and river crossings, and oil, gas, and waterworks pipes. This coating, like single layer FBE (above), can be applied on a wide range of outer diameter (OD) sizes, from 3.5″ to 48″. In most situations, the top layer of abrasion resistance protects against erosion.

- 2LPE Coated Pipe

Two-layer extruded polyethylene coating (2LPE) refers to two layers of pipeline protection. Mastic-based adhesives and polyethylene copolymers are used in the two-layer construction. This provides excellent corrosion prevention, especially at high temperatures.

- 2LPP Coated Pipe

The 2LPP System is a multi-layer powder coating system made up of two functional components. This anti-corrosion system is made up of a layer of polypropylene followed by a coating of high-performance fusion bonded epoxy (FBE).

- 3PE Coated Pipe

To solve the disadvantages of each anti-corrosive procedure, the three-layer polyethylene (3PE) anti-corrosive coating combines the properties of epoxy powder FBE and two-layer PE coating. The principal anti-corrosive agent is FBE. PE primarily protects FBE (mechanical damage resistance) and has excellent water penetration resistance. The three-layer polyethylene coating method provides outstanding mechanical qualities to satisfy the coating material’s properties, and the coating can operate at temperatures as high as 50°C (low density and medium density POLYETHYLENE) or 70°C (high-density POLYETHYLENE) (high-density polyethylene).

- 3PP Coated Pipe

A bottom layer of epoxy powder, an intermediate layer of binder, and an outside LAYER of PP (polypropylene) jacket comprise the three-layer polypropylene (3PP) anti-corrosive coating. The 3PP incorporates all of the benefits of the 3PE while significantly improving its temperature performance in service. 3PP coating is mostly utilized as an anti-corrosion pipeline for transporting high-temperature media and as a pipeline anti-corrosion layer in desert locations with high surface temperatures and lengthy sunshine duration. As a result, subterranean water, gas, and oil pipelines have become increasingly popular in places with high surface temperatures and long daylight duration.

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