How Smart Pigging Technology is Shedding New Light on Asset Health

Stretching nearly 900 miles along the Pacific Ocean, California boasts more than 420 public beaches and close to 330 days of sunshine annually.

With all that sand, sun and salt though, don’t be surprised if your skin or hair feels a little drier. Salt water can be extremely beneficial and rejuvenating in small amounts, but experts warn that prolonged exposure can really dry out your skin because salt deposits can remain on your skin long after you shower off.

Much like our skin, infrastructure is also susceptible to its surrounding environment. Corrosion – or the breakdown or degradation of metallic materials due to an electrochemical reaction when the surrounding environment (e.g. mountain run off, lake, sea, ocean) contains organic materials (sand, gravel, clay, salt) a naturally high moisture content – can lessen the lifespan of pipes and related infrastructure considerably.

But what if we showed you how Jacobs and the San Francisco Public Utilities Commission’s (SFPUC) smart application of magnetic flux leakage technology is providing previously unattainable insight into water main health and resilience – detecting potential defects, such as corrosion, to inform data-backed asset management and capital planning?

NACE International (formerly National Association of Corrosion Engineers) estimated that the U.S. spent about $276 billion annually for control and prevention in 2002 – roughly 3.1% of the country’s total GDP. With inflation and assets increasing in age since, these numbers have risen to more than $1.1 trillion in recent years and made corrosion one of the largest single U.S. expenses.

To help mitigate the issues caused by corrosion and its associated price tag, organizations perform detailed condition assessments of their pipelines, pump stations, storage tanks and corrosion control systems to gauge asset condition and reliability. Jacobs collaborated with the SFPUC and a technology company to develop a revolutionary state-of-the-art condition assessment tool to accurately access cement mortar-lined steel pipeline since none existed at the time. The new technology utilizes a non-destructive magnetic flux leakage (MFL) in-line inspection (ILI) to provide a detailed high-resolution scan.

Since the1960s, unlined steel pipelines, such as those used in the petroleum, natural gas and liquefied gas transportation markets, have been assessed using “smart pigging.” One type of smart pigging uses MFL technology which correlates changes in a magnetic field caused by pipeline defects.

While other markets can use smart pigging technologies to conduct their assessments, water pipelines typically contain lining that limited the effectiveness of MFL ILI and has kept application of this technology on for large-diameter, cement mortar-lined steel pipelines from being a reality.

Until now.

In 2007, the San Francisco Public Utilities Commission (SFPUC), began an effort to study the asset health of approximately 140 miles of large conveyance water lines (56- to 78-in. diameter) within the unique gravity-fed historic Hetch Hetchy Regional Water System which dates back to the early 1900s.

Given that smart pigging technology hadn’t been done at this scale and on large diameter mains anywhere in the world prior to Jacobs involvement with SFPUC, we weren’t just changing the way we did business – we truly were influencing how this technology could be applied for the future.

And our mission was three-fold:

1. Find corrosion damage, find 3rd party damage, document old modifications and repairs and assess joint integrity.
2. Evaluate effect on pressure capacity and leak tightness.
3. Make smart decisions on repairs or replacements.

Using smart pigging technology, our testing and applied method proved capable of improving understanding of pipeline, full circumference and length, and even helped establish locations of weak points for repair and mitigation – helping SFPUC save costs for future replacement and repairs with proactive maintenance.

The ultimate result? A first-of-its-kind application of smart pig technologies for large-diameter mortar-lined pipelines that can be guided by electric tow vehicles (ETVs) and detect losses in wall thickness starting at about 20% with a high degree of accuracy.

Want more? Check out these featured industry articles:

• Trenchless Technology: AWWA Releases Water Main Condition Assessment Manual
• Water Finance & Management: AWWA releases water main condition assessment manual
• Exploratorium: Hetch Hetchy Regional Water System