Maximizing the life of aging pipelines has long been a challenge in North America. Owners of large diameter water and wastewater infrastructure face particular condition assessment challenges, owing to factors such as financial constraints, environmental concerns and access restrictions, which compound the problem.
While desktop studies can help identify pipes with a likelihood and consequence of failure, condition assessment data has been particularly difficult to collect, especially in pressurized metallic pipeline systems. This assessment information is critical, especially for estimating the remaining life in a pipe, or in making decisions on whether to initiate a replacement or repair program.
Despite facing many challenges, pipeline operators now have many more tools to assess, address and manage the maintenance of their transmission systems, enhanced today with the help of modern in-line technologies.
Condition assessment techniques for large-diameter pipelines
A multi-disciplinary toolbox approach is required to ensure that relevant and appropriate information is gathered to enable an accurate assessment of a pipeline’s condition. Different pipe materials and level of accuracy information required will dictate the delivery tools and technologies used.
Metallic water pipelines have typically lacked solutions for conditional assessment and inspection. Other than using indirect methods such as soil corrosion tests, coating assessment and spot inspections, owners of pipelines have had limited choices to locate pipeline stress and establish accurate findings.
In the past few years, however, advances in pipe wall assessment (PWA) technologies have made the screening job more reliable and cost effective, and Pure Technologies (Pure) leads the way with a suite of high resolution/in-line technologies.
Magnetic Flux Leakage inspections
Magnetic Flux Leakage (MFL) is the most accurate of testing methods, and is setting the new benchmark in ferrous wall assessment. PureMFL™ inspections locate and quantify the extent of corrosion in lined and unlined metallic pipes by scanning the full circumference and length of a pipeline at extra high resolutions, without contact with the pipe wall. Extra High Resolution (XHR) geometry sensors detect dents, bulges, wrinkles, buckles and other geometric anomalies.
Until recently, the presence of mortar lining in water pipelines has limited the accuracy use of in-line inspection. With MFL, typically deployed using manned entry methods, pipeline owners can now see through mortar linings up to one inch thick.
PureEM™ for metallic pipelines
Built on Pure’s proven electromagnetic technology, PureEM can be used on a variety of metallic pipe materials such as steel and ductile iron to identify and quantify such as broad areas of corrosion. The technology can be delivered using Pure’s suite of platforms, such as PipeDiver®, PureRobotics® and manned inspection tools.
The PureEM sensors detect pipe wall defects and provide the location and an estimate of the area and depth affected. Upon completion of the inspection, verification may be required to more accurately qualify the wall thickness and provide an estimate on the remaining useful life of the pipe section.
SmartBall PWA and Sahara PWA (Pipe Wall Assessment)
Originally conceived as in-line leak detection tools, SmartBall PWA and Sahara PWA have been developed to also include pipe wall assessment technology in a single deployment. Both the free-flowing SmartBall tool and flexible, free-swimming Sahara tool provide a detailed screening solution for metallic pipelines, which have historically been hard to assess.
The PWA is data is collected simultaneously with leak and gas pocket data, and reads the magnetic field of the pipe wall, which fluctuates when the pipeline is under stress. The presence of stress can be indicative of physical defects like corrosion and cracks, or external conditions such as excessive overburden and point loading.
By combining leak detection and PWA, operators can identify both leaks that could lead to eventual failure, and areas of stress that could represent wall loss or damage.
You can’t manage what you don’t measure
If analysis ranks a utility’s mains as high-risk pipes, it makes sense to utilize high-resolution inspection technologies. High-risk pipes are probably more expensive and more difficult to replace, and probably affect more people if taken out of service. To that end, utilities have come to value Pure’s expertise in helping them sustainably manage their water networks using inspection and condition assessment as the cornerstone to understanding what needs to be addressed.