Pipe coating and pipe lining on and in a pipe

Industrial pipe coating and pipe lining provide complete protection to pipelines

There are some 35,000 kilometres of pipelines criss-crossing Australia, carrying products like oil, gas, water, and refined petroleum from their sources to their delivery points. Pipelines traverse land and sea, experiencing offshore environments, underground environments, undersea environments, and factory environments at the operation base. Each of these environments poses its own problems, and industrial pipe coating needs to work effectively based on a combination of environment, substrate, and the transport material. A pipeline failure can be disastrous, causing the loss of life, environmental damage, and enormous costs in loss, control, and repair. Pipeline coating works to prevent these failures.

In this article we outline how pipeline coating works, and how to choose a pipe coating and pipe lining based on specific needs. We also look at the companies providing industrial pipe coating services and products.

The 5 main types of pipeline coating and pipe lining

With the range of environments and elements that industrial pipeline painting needs to withstand, it is no surprise that there are a wide variety of coatings to meet these needs. The choice of coating depends upon factors such as environment, substrate, use, transportation, and cost. The main pipe coating systems, or the most commonly applied, can be divided into five groups: asphalt enamel, fusion bonded epoxy, polyurethane, three-layer polyethylene, and three-layer polypropylene.

1. Fusion Bonded Epoxy Coating

Fusion bonded epoxy coating (also FBE coating) is an epoxy-based thermoset powder coating. This coating is applied as a dry powder and baked, and can be used for internal or external surfaces of pipelines. FBE coating has excellent chemical resistance, abrasion and impact resistance, and high adhesion, making it corrosion resistant. Suitable for underwater and soil conditions from -40 to 80°C. Fusion bonded epoxy coating is one of the most popular coatings for new pipes and can be used as a base coat for other coating systems or as a standalone.

2. Three-Layer Polyethylene

The three layers of 3LPE coating system are an epoxy (FBE) primer, an adhesive middle layer, and a high density polyethylene outer layer.  3LPE has excellent chemical resistance, electrical resistance, temperature resistance, resistance to mechanical stress, corrosion resistance, anti-aging properties, flexibility, and good environment protection (no heavy metals). With that list of properties it is clear to see why 3LPE dominates the global market.

3. Three-Layer Polypropylene

3LPP coatings consist of a layer of fusion bonded epoxy coating, a middle layer of copolymer adhesive, and an outer layer of polypropylene. They have excellent adhesion, are resistant to corrosion, high temperatures, mechanical stress, and chemicals. Particularly suited to offshore projects due to its mechanical strength and ability to withstand high abrasion environments.

4. Polyurethane Coatings

The high mechanical resistance, chemical resistance, flexibility, ability to withstand harsh weather, UV radiation, and high temperatures, and corrosion resistance of polyurethane works very well for pipeline coating. Underwater environments are particularly suited to PUR coatings. They are also a top choice for repairs.

5. Asphalt Enamel

AE coating is based on bitumen and is used for corrosion protection of steel pipes in the oil and gas industry. They have excellent adhesion to steel, are water resistant, have high electrical resistance, and are resistant to acid and alkali soils as well as bacteria and marine organisms.

What makes industrial pipe lining and coating

Pipelines are protected through the application of both external and internal coating systems. Pipeline coating and tank coating face similar challenges as they need to protect their contents/environment and their substrates from one another.  These industrial pipe coating and lining systems serve several purposes, combining various properties to provide the most comprehensive and effective system of protection. These properties include:

pipe coating and pipelining protecting a long pipe

Pipe coating and pipe lining together provide complete protection to a pipeline.

  • Thermal insulation
     Heat resistance and thermal cycling resistance are important properties when dealing with pipelines. Pipelines run through desert heat and alpine winter. Heat transfer rate and thermal stress need to be kept to a minimum, and the temperature and viscosity of the fluids needs to be maintained.
  • Flow enhancement/assurance
     Fluid viscosities, friction, and turbulence all affect the flow of products through a pipeline. Flow efficiency is important for keeping pipelines clean and preventing buildup, which in turns reduces the number of shutdowns for clean up. This also means that the pumping facilities are not forced to work at a higher capacity thereby reducing energy use.
  • Corrosion resistance
    Corrosion is one of the leading causes of failures in pipelines, costing the world economy billions of dollars a year in prevention and repair. Corrosion for pipelines is an external and internal risk. Externally coatings need to be waterproof as well as resistant to chemicals, salt, and corrosive soils. Internally the coatings need to be able to withstand the corrosive and damaging action of the substance being transported.
  • Abrasion/wear resistance
    The products that are transported through pipelines are not all refined. Many of the fluids contain particulates which, at high speed and pressure, become highly corrosive projectiles which cause wear and abrasion to the pipe. This resistance is also important externally, where the pipe is exposed to harsh climatic conditions.

Special properties by pipeline coating type

All the pipeline coatings have beneficial properties in common; however, they also have special characteristics which define the coating of choice for different projects. The table below shows which pipe coating possesses which special properties.

Chemical resistance
Corrosion resistance
High impermeability
Mechanical resistance
High temperature resistance

For the harshest environments choose a fail safe pipe coating system

The best way to protect a pipeline from corrosion due to a coating failure is to use a supplementary cathodic protection system as well as a coating. Cathodic protection (CP) systems work by converting the metal surface of the pipe into the cathode of an electrochemical cell. This is done in one of two ways: either by imparting a current to the pipe as in impressed current CP, or through providing a sacrificial anode.

The combination of a coating and cathodic protection system needs to be chosen carefully because some coatings do not allow cathodic protection to function effectively.  Coatings that do not disrupt cathodic protection are known as “fail safe” coatings. They allow the electric current to pass through to the substrate, rather than shielding and blocking it. This means that if the coating does disbond, or water seeps between the coating and the substrate, the cathodic protection will work to prevent corrosion at the failure site. The two pipe coating types that allow the use of cathodic protection are fusion bonded epoxy and polyurethane coatings. 

General Australian application procedures of pipe coating and pipe lining

Industrial pipe coating and pipe lining can be plant- or field-applied and each environment presents its own difficulties and benefits. A plant-applied coating is the most economical and has the highest level of quality control and quality due to the controlled environment. A field-applied coating needs to deal with exposure to wind, cold, dust, and bugs, but has the benefit of reducing handling damage. Pipeline repair (pipe relining) and rehabilitation is a key driver for field-applied coating. In the field, two-component liquid epoxies are common, as FBE coating requires preparation of the substrate that needs a factory.

With the thousands of kilometres of pipeline across Australia, it is no surprise that there are many companies operating across the country who cater for industrial pipeline coating needs. The importance of choosing the right coating for environment, use, and substrate, and having the application overseen by professionals cannot be overstated. If you would like more information about pipeline coating, or have a project that requires coating, get in touch! Our experts are here to help. The process is simple: Use our “Request a Quote” or contact forms to tell us the relevant details of your project, and we will collaborate with our coating partners to find the best coating solution for your needs.