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Oil Pipe Rehab
By Aaron Schiflett
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Vendor Team
BERRY PLASTICS
Powercrete coatings
11010 Wallisville Road
Houston, TX 77013
www.berrycpg.com
HARSCO MINERALS
Surface prep
Rossmoyne Industrial Park
5000 Ritter Road, Suite 205
Mechanicsburg, PA 17055
www.harscominerals.com
HOLDTIGHT, LLC
Surface prep
P.O. Box 27907
Houston, TX 77227
(800) 319-8802
www.holdtight.com
SPY (PIPELINE INSPECTION COMPANY)
Quality control equipment
P.O. Box 55648
Houston, TX 77255
(713) 681-5837
www.picltd.com
TINKER & RASOR
Quality control equipment
P.O. Box 1667
San Bernardino, CA 92402
(909) 890-0700
www.tinker-rasor.com
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Pipeline companies are under Federal regulations and some state regulations to maintain the integrity of their pipelines. The requirements can vary depending on the pipeline location, pipe size, and pressure. The regulations can be met by a maintaining a good coating program, proper cathodic protection system, and infrastructure leakage index (ILI) managed programs. By having good programs in place, pipeline owners can also save operating costs during the life of the pipeline.
 Recently, Berry Plastics was approached by a customer who had evaluated some sections of a previously recoated pipeline, and found there were some sections with possible anomalies involving the coating and the wall thickness. The project specification called for bell holes to be dug in each of the anomalous areas to examine the wall loss and coating condition. A bell hole exposes the area of pipe to be repaired rather than digging up the entire pipeline. For example, crews will expose 30' (9.14m) of pipe to coat a 20' (6.09m) section.
Some areas of the pipeline in question required only recoating and others that a repair sleeve be welded in place and then recoated. There were approximately 150 bell holes exposing anomalies on a 24" (60.96cm) 250 mile-long (402.34km) pipeline.
The original pipe coating was coal tar epoxy and some areas had been recoated with a petroleum wax-based anti-corrosion coating. During the course of the specification writing process, several rehabilitation coatings were evaluated and it was determined that Powercrete J would be used on the project. Powercrete J is a 100% solids liquid epoxy designed for girth weld coatings, abrasion resistant overlays (AROs), and rehabilitation operating temperatures up to 140°F (60°C). Powercrete J has a track record of outstanding performance in many applications for over 20 years. This history is supported by testing performed by the Gas Technology Institute.
 Other coatings that were evaluated included epoxies, urethanes, epoxy/urethane blends, and composite coatings that required additional personal protective equipment (PPE) and environmental processes that were not required with the Powercrete J. In fact, during the previous application of the urethane products, the contractors were required to wear respirators and properly working clean air sensors. Fans were also required at the bottom of the bell holes and/or any containment that might have been required.
Contractors were selected based on their ability to expose the buried pipe, remove old coating, clean the pipe, repair the pipe wall, weld the repair sleeve (if needed), media blast to NACE No. 2/ SSPC-SP 10 Near White standard with a 2 to4 mil (0.05mm-0.10mm) profile, and hand-apply the coating according to the Powercrete J Manual application guidelines.
There were 11 contracting crews awarded the job, including the owner’s own crew. Most of the contractors were local to the Kentucky region and had worked with the pipeline’s owner in the past.
Expose And Clean
Each contractor was given approximately 10 bell hole sites. The individual sections could vary in length—a section could be 2' (0.61m) long or it could be 20' (6.09m) long—it depended on the anomaly to be repaired. And with a pipeline covering 250 miles (402.34km), the jobsite terrain greatly varied. Some of the sites were in fields and were  easily accessible. Some could only be reached with the help of four-wheeled all-terrain trucks. A few ran behind houses and could only be accessed from sun-up to sun-down due to neighborhood restrictions. In one memorable instance, the crew dug a bell hole and went home for the evening. That night 3 ½" (8.89cm) of rain fell. The crew spent the next two days pumping water out of their freshly dug bell hole before they could access the pipeline.
Regardless of the jobsite terrain, once the pipe was exposed, the crew removed the original pipeline coating. If the pipe had been previously coated with wax tape then that was also removed. Traditionally, it is believed that once wax coating is applied to the pipe nothing else can be applied to the pipe. However, during this project, the owner set out to clean the pipe to a level that a liquid epoxy could be applied to the pipe. This was accomplished through a multiple step process. First, the wax was unwrapped and scraped off using putty knives, hammers, and chisels. Then the pipe was cleaned with a high pressure wash of mild soap and water. This was followed by a pressure wash spray-application of the surface cleaning product, HoldTight Solution.
Per the specification, the cleaning of the substrate had to remove any remnants of old coatings from the surface profile of the steel substrate. The owner was satisfied that the waxy residue had been removed at each of the bell holes and the pipe was cleared for the next stage in the Powercrete J application process: repair and weld on sleeves if necessary.
Repair And Coat
The type of anomaly determined the type of repair to be conducted. If the steel thickness of the pipe’s walls was too thin, the crew would place a metal sleeve over the weak spot and weld it into place. The substrate was then blasted with Black Beauty blast media to NACE No. 2/ SSPC-SP 10 Near White standard with a 2 to 4 mil (0.05mm-0.10mm) profile.
 Next, the crews mixed the Powercrete J coating from two-part kits, mixing by hand or by drill. The epoxy was then applied to the pipe in thin layers of 10 mils (0.25mm) to be built up to a total thickness of 30 to 40 mils (0.76mm-1.02mm).
The pipeline that was involved in this project was in service during this complete project, which was at an operating temperature of approx. 55°F (12°C). This created a very thin window each day that the coating could be applied before the pipe would begin sweating. To control the moisture condition of the pipe, the contractors erected inflatable tents around the bell hole areas. During the course of the three-month-long-project, the weather went from mid-spring to summer and the contractors had to use a combination system of dehumidification equipment and heaters, then switch to air conditioning to control the moisture on the pipe, as well as ambient conditions during the coating application and full cure. The coating was then holiday tested using Spy and Tinker & Rasor holiday detectors and the bell holes were then backfilled.
The selection of the proper coating for a particular project it is important to not only review test reports and the history of the product’s performance but also to consider the total picture of the product selection, because factors including PPE requirements, substrate preparation, and, of course, the application process, can affect the long-term performance of the coating. As this long and highly detailed pipeline project proved, at each step of the process all concerned parties should be involved and have a full understanding of the project requirements. For a successful pipeline project, all the players must be involved at every turn in the pipeline, as it were.
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