In previous blog posts, we’ve spoken about how coatings can fail in industrial facilities, especially in water immersion conditions. This post will discuss the variety of options that an industrial plant has to repair leaks in critical water piping systems like circulating water lines, fire suppression lines, and service water lines. We will explore the benefits and disadvantages of four common types of repairs; Moisture-Cured fiberglass wraps, External Pipe Clamps, External Welded repairs, and Carbon fiber composite repairs. Moisture-Cured, Fiberglass Wrap Repairs A moisture-cured urethane (MCU) fiberglass wrap along with a fast cure epoxy stick is a common repair technology for leaking piping systems. The advantages of this technique are the potential for installation over actively leaking pipes and quick, easy, and cost-effective installation. An MCU wrap can typically stop a water leak that is below 50 psi in internal pressure. However, this technology has poor adhesion value and can only serve as a temporary repair option, designed to provide less than six months of service life. Further, it is very difficult to stop leaks located at a section of the pipe that is not smooth and straight. Leaks near weld seams, flanges, on T’s, or near interruptions can be very difficult or impossible to repair with this technology. Large Diameter, Fiberglass Water Line with GF-130 MCU Leak-Stop External Pipe Clamps External pipe clamps are an excellent option for fixing a leaking pipe on small diameter piping. Not only are they readily available, but they are light and easy to apply. Clamping repairs get much more difficult with larger diameter pipes. They get much heavier and are not always readily available with larger pipe diameters. While clamps can be applied easily to a water leak, it is vital to ensure that the clamp design is compatible with the system’s full design pressure. External clamps can be considered long-term repairs; however, they significantly increase the likelihood of a future leak in the area. Clamps utilize a bolting technology that can lose tension over time, the gaskets can embrittle with temperature changes, and they often suffer from external corrosion. Finally, these clamps do not work over pipe geometries that are not straight, uniform, and away from any interruptions like a weld seam, pipe support, joint, or flange. Large diameter clamps can be very heavy and require a crane for installation. External Clamp Installed over Water Line in a Wastewater Plant Specialty Clamp Design for Higher Pressure Pipes External Welded Repairs Many industrial plants have their certified welders on their maintenance team, making an external weld repair on a water pipe relatively easy and economical. After getting a metal plate bent to the pipe’s radius, a patch can be easily welded to the exterior to provide a leak repair. The biggest issue with an external weld on a water pipe is the degradation of the water pipe’s internal coating. The heat associated with the welding process degrades the internal coating and causes subsequent corrosion adjacent to the welded repair. For through-wall failures, the pipe must be taken out of service before installing a welded repair. If welded repairs are being used on water pipes, the internal coating must be repaired after installation. Otherwise, a pipe should be proactively reinforced. It is not a matter of if a welded repair will leak; it is a matter of when. Installation of a Welded Repair On Water Pipe Carbon Fiber Composite Reinforcement Carbon fiber composite repairs systems offer several advantages for pipe repairs. First, they can be installed on pipes of any size, shape, or diameter. They are lightweight, even for large diameter repairs, and compatible with a wide range of pressures, up to 3,000 psi internal pressure. Carbon fiber composites work with difficult locations like a joint, welded connection, or adjacent to a flange, and they provide a long-term solution to pipe leaks. The installation is relatively easy and economical; however, it does require proper surface preparation and training of the staff performing the installation. On the downside, Carbon fiber composite repairs require a 24-hour cure prior to taking direct pressure. The pipe must be shut down for the repair; otherwise, another technology must be used to stop the leak temporarily. Advanced FRP Systems specializes in carbon fiber composite pipe repairs. We have carbon fiber pipe repair kits readily available for any pipe size. Before and After on a Circulating Water Line Repaired With Carbon Fiber Carbon Fiber Repair on Elbow Section with Interruptions Carbon Fiber Repair on an Elevated Temperature Water Line Running at 180 oF Comparison of Technologies LEAK SCENARIO RECOMMENDED SOLUTION Leak on Straight Pipe Below 10” Diameter A commercially available external pipe repair clamp is an excellent choice for this small diameter pipe repair. Leak near flange or other interruption on a pipe An MCU wrap can be used to stop the leak, followed by a carbon fiber composite reinforcement system for a long-term solution. Leak on a large diameter piping system, above 36” Carbon fiber composite repair is an excellent solution for large diameter pipes as they are lightweight and easy to install. Requires an MCU wrap to stop leak or pipe depressurization. Leak on a Pipe Elbow Clamps do not work on elbows, so a Carbon fiber composite system in conjunction with an MCU wrap should be used for a permanent repair on any pipe sections that have a radius. Leaks on uncoated water pipes Weld repairs are an excellent option for uncoated piping systems. If pipes do not have an internal coating, they should be made out of a corrosion-resistant material, or active corrosion will occur. Leaks on pipe joints; bell and spigot, flanges or welded junctions Either a fast-cure epoxy stick or an MCU wrap should be used to stop the leak temporarily. A carbon fiber composite system can then be installed over the joint to provide a long-term, maintenance-free solution. Leaks on Stainless Steel Pipes Weld repairs can be performed as long as the patch and weld materials match the grade of steel on the host pipe. Carbon fiber composite repairs are compatible with all types of metallic pipes, including stainless alloys. Summary We have explored several traditional methods of water pipe repairs to get your systems back up and running quickly and reliably. It is crucial to look at each of these systems’ advantages and disadvantages when deciding your facility’s correct solution. If you have further questions or want to learn more about repairs on pipes, feel free to reach out to Advanced FRP Systems. We offer a free consultation with a corrosion expert, custom failure analysis reports, and inspection services to determine the state of your infrastructure. Whether the inspection is done in house or in conjunction with us, Advanced FRP Systems is here to thoroughly diagnose your corrosion problems and prescribe streamlined, custom solutions. You can trust us to take the time to dive into your unique problems and build the right custom solution or a preventative measure.