The Critical Need for Advanced Phased Array Ultrasonic Testing (PAUT) in Pipeline Inspections: Lessons from Past and Present

The Persistent Threat of Undetected Defects: Don’t Let What You Can’t See Hurt You

Even today, undetected volumetric defects in pipelines remain a significant hazard. Issues such as corrosion and weld flaws can go unnoticed if proper inspection methods aren’t used, leading to leaks, ruptures, or explosions. While conventional inspection methods like magnetic particle inspection (MPI) or radiographic testing (RT) and manual ultrasonic testing (UT) still dominate some regions and certain sectors, they are often inadequate for detecting complex or subsurface flaws, particularly in aging pipelines.

The risk of relying on these outdated methods is compounded by the fact that pipelines in use today are decades old. With infrastructure aging and demand for safe, reliable energy transportation rising, ensuring the structural integrity of these pipelines has never been more crucial.

Case Studies: Pipeline Disasters That Could Have Been Prevented

San Bruno Pipeline Explosion (2010)
In 2010, a natural gas pipeline explosion in San Bruno, California, caused by flawed welds, claimed eight lives and destroyed 38 homes. The subsequent investigation found that undetected welding defects played a critical role in the disaster¹. Advanced phased array ultrasonic testing could have detected these flaws, offering the precision and clarity needed to prevent such failures.
Marshall Oil Spill (2010)
The 2010 Enbridge pipeline rupture in Michigan spilled over one million gallons of crude oil into the Kalamazoo River. Fatigue cracks, exacerbated by corrosion, had been identified in prior inspections but were left unaddressed². Eddy current array inspection could have detected the fatigue cracking, and PAUT’s enhanced sensitivity to corrosion could have prompted earlier action and averted one of the costliest inland oil spills in U.S. history³.
Plains All American Pipeline Oil Spill (2015)
In 2015, a Plains All American pipeline near Santa Barbara, California, ruptured and spilled an estimated 2,934 barrels of crude oil, contaminating beaches and marine ecosystems. Severe corrosion had significantly thinned the pipeline walls, which went undetected by traditional inspection methods⁴. PAUT’s ability to accurately assess wall thinning and subsurface corrosion could have prevented one of California’s most significant oil spills.

Why Traditional Inspection Methods Are Yesterday’s News

Though incidents like those in San Bruno and Marshall are often seen as historical, they underscore risks that persist today. The conventional NDT techniques still in use in many regions, such as radiographic testing and manual UT, have several limitations:

Limited Detection Capabilities: These methods struggle to identify small volumetric defects in complex geometries.

Incomplete Data: Traditional techniques often provide partial coverage, making it easy for flaws to go undetected.

Time-Consuming: Older methods require more time for both scanning and analysis, reducing efficiency and increasing the risk of human error.

Recent Incidents: Proof That We’re Still Not in the Clear

Despite increased awareness, recent data shows that the risks of undetected pipeline defects remain a present-day issue. In 2023, the U.S. Pipeline Hazardous Materials Safety Administration (PHMSA) reported 614 pipeline incidents, resulting in $334 million in property damage. Many of these incidents were caused by corrosion (28.2%) and mechanical/material failures (42.5%)⁵—failures that could be significantly reduced with more advanced inspection methods like phased array ultrasonic testing.

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Globally, aging pipelines are still prone to failures. For example, in 2021, a fire broke out on an underwater gas pipeline in the Gulf of Mexico after a leak⁶, drawing attention to ongoing integrity risks in pipeline infrastructure.

The Clear Advantages of PAUT: Because Nobody Wants to Deal with a Surprise

The precision and efficiency offered by PAUT make it the go-to solution for modern pipeline inspections. Compared to traditional methods, PAUT offers several key benefits:

Enhanced Sensitivity: PAUT can detect the smallest flaws, offering superior detection of corrosion and weld issues.

Comprehensive Coverage: PAUT scans can cover large areas quickly, providing detailed images of even the most complex pipeline geometries, with data recorded to demonstrate complete area coverage.

Real-Time Data: PAUT offers immediate feedback, helping operators address issues more quickly and effectively.

A study comparing phased array ultrasonic testing to radiographic testing⁷ found that PAUT "outperforms RT in terms of the Probability of Detection (POD), particularly for critical planar flaws," demonstrating its effectiveness in identifying defects in pipeline welds. This increased sensitivity and accuracy not only enhances the reliability of inspections but also leads to improved risk management and significantly reduced chances of catastrophic pipeline failures. By adopting PAUT, operators can ensure a more proactive approach to pipeline integrity, safeguarding both infrastructure and public safety.

Gaps in PAUT Adoption: Why Some Still Gamble with Safety

Despite its advantages, the adoption of PAUT is not yet universal:

Cost Sensitivity: Smaller operators or those in cost-sensitive regions may still rely on older methods due to the higher initial investment in PAUT equipment and training.

Regulatory Lag: While standards bodies like ASME or ISO recommend PAUT for critical applications⁸, enforcement and adoption of these standards can vary, particularly across international markets.

Aging Infrastructure: Many pipelines, especially in North America and Europe, were built decades ago and weren’t designed with modern inspection technologies in mind, creating barriers to effective implementation of PAUT.

From Past Mistakes to Beyond Current Safeguards—The Role of PAUT

The importance of adopting advanced NDT solutions, like PAUT, cannot be overstated. Recent incidents, combined with the proven track record of past disasters, show that many pipeline failures could have been avoided with proper inspection methods. By investing in PAUT technology, operators can ensure safer operations, reduce the risk of undetected defects, and ultimately prevent the next disaster.

Eddyfi Technologies is leading the way with innovative PAUT solutions designed specifically for pipeline inspections. With high-sensitivity detection capabilities and faster, more accurate results, PAUT is the clear choice for operators looking to safeguard their infrastructure. Check out our free resource to learn how to turn pipe (inspection) dreams to reality here.

Don’t Let Your Next Inspection Be a Horror Story

As pipelines continue to age and global energy demands grow, the need for advanced inspection technologies has never been more urgent. The risks of missed defects—whether due to outdated inspection methods or incomplete data—are simply too high. By adopting advanced phased array ultrasonic testing, operators can ensure the safety and integrity of their pipelines, protecting both the public and the environment from future catastrophes.