Author: Lewis Barton
What is the Future of Direct Assessment for Unpiggable Pipelines?
In a nutshell:
Direct Assessment has long filled the unpiggable inspection gap, but its corrosion only scope and growing limitations no longer meet the industry’s evolving risk landscape. As data volumes surge, technology accelerates, and experienced engineers retire, operators need a new approach – one that delivers broader threat coverage, stronger predictive capability, and clearer, defensible decisions. ROSEN’s Non-Intrusive Pipeline Assessment (NIPA) represents this next step. By integrating advanced above ground inspection, AI driven predictive analytics, and the industry’s most comprehensive integrity data repository, NIPA transforms unpiggable pipeline management from reactive corrosion checks into multi-threat, data driven integrity assurance. The result is fewer excavations, justification for making selected pipelines internally inspectable, reduced lifecycle costs, improved safety, extended asset life, and a unified, accountable pathway to managing assets that were never designed for traditional inspection. Lewis Barton provides further details on how NIPA supports integrity and safety in environments where conventional in-line inspection (ILI) methods cannot be applied.
Despite technological advancements, a significant portion of the global pipeline network is still classified as “unpiggable.” These pipelines present unique challenges due to physical constraints, such as tight bends, diameter changes, and a lack of launch/receive facilities. They also have operational limitations tied to production schedules and flow conditions. In many cases, retrofitting for ILI is simply not economically feasible and will never be a reality due to budget constraints. However, the inability to pig an asset does not mean that operators are able to bury their heads in the sand and do nothing.
Operators are under growing pressure to demonstrate that their pipeline networks are safe for operation – including assets that operators deemed to be “unpiggable”. In-Line Inspection can provide information on metal loss, cracking, impact damage, ground movement, and thermal expansion issues covering many of the key threats to pipeline integrity. Consequently ILI data is the bedrock of most pipeline integrity management programs. When a pipeline is unpiggable there is a gap in the data and hence the IMP. This unpiggable gap calls for innovative approaches, beyond intrusive inspection tools, to ensure effective monitoring and maintenance of even the most complex assets. Direct Assessment (DA) has been the pipeline industry’s primary means of filling the unpiggable gap for over two decades.
DA, however, only addresses a single threat class: corrosion, with separate approaches defined for internal corrosion (ICDA), external corrosion (ECDA), and stress corrosion cracking (SCCDA). According to data from the Pipeline and Hazardous Materials Safety Administration (PHMSA), corrosion is responsible for less than 20% of recorded pipeline failures. Although it is true that corrosion is one of the key contributors to pipeline failures, the DA scope does not support managing other integrity threats, such as third-party damage, geohazards, or material and weld defects. This means that the majority of risk factors and threats fall outside DA’s field of view. While it is a practical necessity and obligation for many, its inherent weaknesses are prompting a reassessment of DA’s current role, efficacy, and future.
The industry needs a bridge – an assessment model based on the principles of DA that delivers increased confidence and multi-threat coverage for difficult-to-inspect assets where in-line inspection cannot be achieved. Additionally, it must build on the latest developments in data-driven integrity management and AI tools to meet modern expectations.
Drivers of data-driven integrity management
Best practice in pipeline integrity management is, of course, constantly evolving, with the bar being raised by technological or process breakthroughs or more stringent regulatory requirements. While the industry has evolved from reactive responses to proactive risk-based programs, leading-edge operators are embracing predictive models supported by AI-enabled data analytics.
There are three primary factors driving this shift:
1. Increasing data volume: Operators now generate terabytes of data from which they could gain insights. However, only a fraction of this digital ‘gold’ reaches or informs decision-making regularly. Realizing this value requires platforms that can ingest varied data streams, analyze and correlate them in near real time, and apply machine learning models to estimate where and when risk may develop.
2. Technological advances: Developments in technology, such as cloud computing, now enable the analysis of data at a speed and scale that was impossible a decade ago. These tools reduce the cost of evaluating assets by integrating the outputs into a risk-based integrity management framework.
3. Human capital pressure: The “silver tsunami” of retirements from the baby boomer generation is thinning the pool of experienced engineers with real-world experience and organizational knowledge. At the same time, hiring budgets are flat, and public scrutiny is rising. Doing “more with less” is becoming a practical reality.
Collectively, these trends are quickly moving the industry beyond proactive prevention into predictive integrity programs, not out of wanting, but out of necessity.
As the industry grapples with aging infrastructure and a shrinking engineering workforce, the challenge of unpiggable pipelines affect the industry more than ever. Traditionally sidelined by inspection limitations, these assets always required a creative integrity management approach and are now entering a new era – driven by data.
The today and tomorrow of DA: Introducing NIPA and the Integrity Data Warehouse
Operators need breadth without complexity, which is why ROSEN developed the Non-Intrusive Pipeline Assessment (NIPA) service. Our integrated model brings acquisition, analysis, on‑site NDT, and remaining life‑prediction together – eliminating the interfaces that dilute accountability and enabling a single, threat‑agnostic view of asset condition.
NIPA, fueled by advanced above ground inspections such as Large Standoff Magnetometry (LSM) and the unique ROSEN Integrity Data Warehouse (IDW), is what ROSEN sees as the future of unpiggable pipeline integrity management.
True to the core principles of DA, NIPA integrates multiple above‑ground screening and monitoring technologies with supporting data to generate information. However, NIPA takes this process a step further by harnessing the power of big data and AI through pipeline condition prediction models, and incorporating LSM inspection into a single, orchestrated field campaign. The result is a unified, multi-threat analysis program fit for the future – i.e., Direct Assessment 2.0.
The core elements of NIPA include:
- LSM: Detects anomalies in a pipeline’s magnetic field caused by metal loss, mechanical damage, or local stress concentrations (e.g., weld misalignment) – with high‑resolution detection accuracy, enabling the identification of defects beyond simply corrosion.
- Internal flow modeling: Using flow dynamics to predict where internal corrosion is active within the pipeline and enabling us to rank which low points are the most critical or if Top of Line corrosion is possible.
- Cathodic protection and coating diagnostics: The core elements of DA integrate coating survey results (e.g., DCVG, ACVG) and CIPS data to assess CP shielding, disbondment, and cathodic protection performance.
- Predictive analytics: Predictions of corrosion presence and depth are made using machine learning models trained on the IDW, the industry’s most comprehensive integrity knowledge base. An enabling data store containing historical in‑line inspection data sets for over 27,000 unique pipelines and incorporates geospatial data, pipeline design properties, and operator‑provided records.
- Targeted in‑ditch NDT: An essential part of effective pipeline integrity management is to verify reported anomalies and confirm dimensions. NIPA analysis identifies precise areas where anomalies or degradation may exist - avoiding unnecessary excavations.
- Fitness for Service Assessment: Assessment of in-field findings using appropriate methods and techniques based on international best practice. Determining safe operation limits, repair demands, and remaining life.
NIPA’s integrated inspection suite provides coverage across multiple threat classes:
- External and internal corrosion damage.
- Identification of areas susceptible to stress corrosion cracking.
- Third‑party strikes, dents, gouges, ovality, and illegal tapping.
- Geohazard‑induced strain, buckles, and spans.
- Coating degradation and CP shielding.
- Manufacturing and construction flaws.
In ROSEN’s experience, integrating additional LSM and predictive analytics data streams into its NIPA methodology reduces unnecessary excavations by more than 50 percent compared to corrosion‑only DA, thereby increasing first‑dig hit rates of critical assets with a track record of 100% alignment of defect ERF classifications above 0.9 in verified locations.
What does this mean for pipeline operators?
For business leaders, NIPA provide defensible risk‑reduction and can strengthen insurance discussions while extending the life of unpiggable assets without requiring significant capital expenditure. For asset managers, it brings together disparate workflows to one accountable partner, halves unnecessary excavations, justifies investing in making selected pipelines internally inspectable, and accelerates decision cycles.
The historical direct assessment process can and is being transformed by AI and data analytics through the ROSEN NIPA process. By fusing pipeline histories, CP data, environmental conditions, and operational trends, we can build predictive models that replicate, as far as possible, the insights of ILI and engineers. This is integrity management in the style of big tech: turning vast, fragmented datasets into decision‑ready intelligence.
Our goal is to totally reimagine how we understand and manage the safe and reliable operation of pipelines that were never designed to be internally inspected.
The path forward in unpiggable pipeline integrity
Direct Assessment will remain a regulatory fixture. However, the future of safe, economical pipeline operation for unpiggable assets rests on approaches that extend beyond corrosion. Only by integrating multiple data streams, and turning disparate data sets into actionable intelligence will operators improve their integrity management and reduce the risks associated with unpiggable pipelines. NIPA closes the gap by:
- Reducing incident probability through multi-threat detection.
- Cut total lifecycle costs by eliminating more than half of unnecessary digs, maximizing uptime, and deferring major capital projects.
- Extend useful economic life with evidence-based repair strategies and adaptive reassessment intervals without costly physical modifications.
- Strengthen compliance and insurance positions via transparent data lineage, beyond-minimum threat coverage, and benchmarked performance metrics.
For operators, these gains translate into lower enterprise risk, an improved return on invested capital, and Environmental, Social, and Governance aligned stewardship. For asset and risk managers, they provide a single, defensible roadmap for inspection, modification, repair, and budget prioritization, supported by one accountable partner, rather than a patchwork of contractors. The ROSEN NIPA process, and its novel approach to unpiggable pipeline integrity, delivers measurable business value to operators:
- Safety and environmental assurance: Early identification of external interference damage enables targeted repairs, reducing the probability of loss‑of‑containment events.
- Regulatory resilience: NIPA not only demonstrates compliance with the requirement to implement DA, but also a commitment to exceeding the prescriptive minimums of DA standards.
- Fewer excavations, lower direct spending: Targeted anomaly ranking means operators only dig where integrated data justifies excavation. This can translate into millions of dollars in savings per integrity cycle.
- Minimized unplanned shutdowns: Early detection of high‑growth defects can give operators the opportunity to conduct repairs during planned outages, reducing unplanned downtime.
- Consolidated data analysis: With the IDW’s consolidated dataset, engineers skip the tedious work of reconciling spreadsheets and gathering external reports.
- Bottom‑line impact: Across direct, indirect, and transferred expenditures, ROSEN clients often recover their investment in NIPA within the first assessment cycle.
At the enterprise level, these benefits translate into extended asset economic life, deferred capital expenditures, more predictable asset write‑downs, and improved portfolio resilience.
If an integrity program is still driven by corrosion-only DAs or limited by piggability constraints, now is the time to evaluate NIPA.
Lewis Barton
Service Manager, ROSEN Group
Lewis has been with ROSEN for 14 years, providing technical consulting for global projects. His experience spans various areas, from flow assurance to pipeline inspection, but he has always specialized in unpiggable pipeline integrity. Today, he leads ROSEN's Above-Ground Services portfolio, developing and delivering non-intrusive inspection solutions for pipelines and critical assets - combining novel technologies with proven conventional methods to enhance integrity management.
Jabbar Mirzoev
Global Business Line Manager NDT Diagnostics
Jabbar has spent more than 18 years in the oil, gas, and petrochemical sectors, leading international teams and driving business development across the CIS and Central Europe region. With a strong blend of technical and commercial expertise, he has specialized in in-line and robotic inspections, and advanced NDT technologies. Today, he holds a global business leadership role at ROSEN, guiding NDT service development and market strategy while advancing innovative integrity solutions for critical pipeline and industrial assets.