Pipeline coatings shield pipelines from one of the greatest threats to pipeline productivity—corrosion. Coatings serve to protect the infrastructure of pipelines and is a vital aspect in the quality of oil and natural gas transportation.

Due to the recent boom in domestic natural gas, an increasing number of pipeline systems are being laid throughout the country, and each pipe requires external coating. With all of these new oil and natural gas pipelines, it is no surprise that the coating industry is expected to grow substantially in the upcoming year.

Much of the existing industry is using this influx of growth and opportunities to expand their own products and services. Aiding and monitoring these expansions is the National Association of Pipeline Coating Applicators (NAPCA). The association is comprised of plant-applied pipeline coating companies from around the world. NAPCA works to standardize coating practices and in turn, provide both its members and their customers with the high standards of quality and workmanship necessary to protect the world's pipeline infrastructure.

FBE and ARO

Overwhelmingly, the most widely used pipeline coating in the U.S. is fusion bond epoxy (FBE) coating. FBE is a powder coating that was developed in the 1970s and is still considered the most reliable coating available in the pipeline coating industry. Modern external coatings like FBE are primarily designed to produce a holiday-free product and most importantly, to protect pipelines from corrosion over long periods of time.

In the FBE pipeline-application process, the powder is exposed to high temperatures under which the contents melt, and powder then transforms into a liquid form. The liquid FBE film then flows onto the steel surface of the exterior of the pipe on which it is applied, and it soon becomes a solid coating, covering the entire surface of the pipe. This liquidation process is called fusion-bonding, thus giving the coating its name.

“Prior to the development of FBE coating, cold-tar enamel was used to coat the pipes. Some of these coatings are still in the ground today 50 and 60 years later.” —Joel Chermak, general manager of Midwest Pipe Coating Inc. and president of NAPCA

"Fusion bond epoxy is still the number one coating in the oil and gas industry for a reason," says Joel Chermak, general manager of Midwest Pipe Coating Inc. and president of NAPCA. "I think it's the best. It's what everyone uses right now. There have been great results with it and I think that the industry will continue with that coating for some time to come."

Luther Winch, owner and partner of Ball Winch Pipeline Services LLC agrees, maintaining that FBE coatings work the best in his experience. Yet, however reliable the FBE coating may be, it is not designed for high impact instillation. To compensate for this, abrasion resistant overlays (ARO) are often applied on top of anti-corrosion coatings like FBE, as Chermak explains.

"For example, if a pipeline needed to be laid under a highway, the workers would not tear up the entire highway. Instead, they use directional drilling to drill a hole under the highway, then pull the pipe through. This process could damage the anti-corrosion coating on the pipe, so the ARO coating is applied on top of the anti-corrosion coating."

Essentially, the ARO coating protects the coatings that protect the pipes. ARO coating is not only used in directional drilling, but is also applicable when installing pipelines in bores, river crossings, and various rough terrains.

Because ARO is often paired with FBE coatings, and because of its specific protective coating abilities and instillation similarities to FBE coatings, ARO is sometimes referred to as FBE dual coating.

Three-layer coatings

Additionally, pipeline companies have coating options other than exclusively FBE and ARO.

"While FBEs and AROs are the most popular coatings, three-layer application coatings preform very effectively as well," says Winch. "There are also certain liquid products that I have seen do well."

Winch explains that when choosing the most effective coating for a particular pipeline system, external coating choices are more related to environmental conditions like the specific terrain at the place of installation, such as the soil type and high service-temperature exposures.

For example, pipeline systems transport oil and natural gas all across continents. This means that many transportation pipeline systems are installed underwater. Today, FBE coatings are applied to pipelines serving a wide variety of terrains and climates, including high-pressure subsea installations.

According to Winch, "In some cases offshore installations require heavy-walled pipe or concrete-coating applications to serve as an anti-buoyancy measure, but FBE is still used as the primary coating."

Chermak agrees, stating, "The coatings we use are basically all the same. Conditions such as climate or terrain rarely affect the coating type, so it can usually be used underwater with no problem."

Interior coatings

Meanwhile, in addition to the outside, coatings are occasionally applied to the interior of the pipes as well. Internal flow efficiency (ID) coatings are applied to create a smooth and defect-free surface on the inside of the pipe. The purpose of ID coatings is to increase the flow efficiency of the pipes.

"ID coatings are most popular among transportation pipes with larger diameters in the oil and gas industry," explains Chermak. "By using ID lining, companies can then downsize their process at their pumping stations, because less horsepower is needed to push the gas through the pipe line."

Transportation pipes that use internal coating more frequently are large-diameter pipes, usually between 18- to 24-inches, and are used to move products between cities, countries and even continents.

Prior to an ID-coating application, the inside of the pipe must be thoroughly cleaned of dirt, which will sometimes adversely affect pigging operations if loosened. Additionally, as a result of the increased flow efficiency, the cost of operating the pipeline is lowered.

In fact, as a general rule of thumb, pipeline coatings usually cost about one-tenth of the price of the actual pipe, say the executives. Prices deviate slightly from this price with each coating company's individual business practices.

New pipeline markets

New markets are arising every day for pipeline-coating suppliers. In fact, the Interstate Natural Gas Association of America (INGAA) Foundation reports that 32,000 miles of additional pipeline will be installed in the U.S. by 2030.

In addition to coating all of the new pipelines, the coating on old pipelines must eventually be replaced. Older coatings are not as effective as those being installed today. As a result, over time the coatings have weathered away are no longer actively protecting the pipelines against corrosion.

"Prior to the development of FBE coating, cold-tar enamel was used to coat the pipes," explains Chermak. "Some of these coatings are still in the ground today 50 and 60 years later."

While the cold-tar enamel is still coating the older pipelines, pipeline companies are actively working to replace the old coating with newer, more effective coating. Yet, it is difficult to identify whether the older coating on pipeline does in fact need to be replaced on a specific pipeline.

Winch admits that the longevity of a coating depends on many factors. "We just excavated a 90-year-old pipeline that was coated with cold-tar enamel, and the pipe was in such good shape that it was used for an architecture project."

Some underground areas are just not susceptible to corrosion, he says, thus the old cold-tar enamel coatings are still sufficient. However, there is no exact science to predict which coatings need replacing.

"It's hard to say if the pipeline industry will face these same problems half a century from now with FBE coatings, because it only became widely used in the 1980s," says Chermak

Future technologies

Pipeline coating companies are always searching for ways to improve coating systems, and it is possible that FBE will be replaced with even more efficient coating technologies in the future.

With pipeline business on the upswing, coating companies are developing new products and actively researching ways to better coat specific types of pipelines.

"We have recently developed a three-layered polyethylene (PE) and polypropylene (PP) pipe-coating system, inclusive of touch-down pipe and risers," says Winch. "Ball Winch-Triplus PE-PP is to be used for critical applications for subsea pipelines. Triplus PE is also used where impact and abrasion requirements may be severe."

In addition to developing new systems, Ball Winch is expanding its business by adding a 5,000 square foot expansion to its facility and adding more types of coatings.

"Many coating companies are following the same pattern of expansion as of late," he says. "In a recent research study, it has been predicted that the pipeline industry will experience an 85% growth rate in the coming year. With so many pipeline companies planning to both expand and refinance, this is a prime opportunity time for coating companies."

Comments