Q & A: Risk-Based Inspection for Controlling Pipeline Corrosion

March 2017, Vol. 244, No. 3

Maintaining the integrity of oil and gas pipelines and complying with increasingly strict regulations have enabled operating and service companies to extend the lifetime of these critical assets while ensuring safety and protecting the environment. Technological advancements for controlling corrosion – the second-leading cause of pipeline failure after third-party damage – as well as the growth in implementation of corrosion-management plans are serving to prevent the adverse effects of corrosion while reducing overall costs.

One process crucial to the success of a corrosion-management program is risk-based inspection. This analysis methodology is used to assess the probability of failure and its consequences associated with each component of an asset. Consequences include risk to public safety, environmental damage, product loss, and costly expense. Risk-based inspection programs revolve around understanding risk, risk drivers, and where equipment is in its lifecycle, and then prioritizing inspection-related activities.

To address how risk-based inspection programs have been conducted in the past up through today, including their benefits and challenges, NACE International formed a panel of three pipeline corrosion experts who answered a series of questions on implementing and managing these systems. They are NACE members Tony Alfano of DNV GL, Jeffrey L. Didas of MATCOR, Inc., and David H. Kroon, FNACE of Aegion Corp.

NACE: In your career as a corrosion-control expert working on pipelines, when did you first begin implementing risk-based systems and why?

Alfano: I would consider myself more of a risk-management expert working on pipeline corrosion rather than the other way around. Over the past 10 years, I have helped my clients develop systems to support risk-informed decision-making. There were two main reasons for moving in this direction. The first was prioritization.

Even for assets with prescriptive code repair requirements, there remained the question of how to prioritize necessary repairs with similar repair-timing requirements. Without a risk-informed approach, these decisions are almost exclusively driven by cost and convenience. While those are certainly two important aspects of the planning process, knowing which decisions have the greatest reduction on the overall risk liability of the company provides a more complete understanding to leverage when making these decisions.

The other main reason to utilize risk-informed approaches was optimization. Operational budgets are finite, so establishing risk-informed decision processes allowed the pipeline operators to ensure these resources were optimally invested. This is particularly important when managing assets without prescriptive repair guidance, or when evaluating additional preventative or mitigating measures that can be undertaken beyond prescriptive guidance.R

Didas: PHMSA regulations are getting more prescriptive, and incorporating risk-based systems into a prescriptive system is difficult but can be managed. Once you have incorporated the PHMSA policy into your policy and procedures and developed a plan on how to manage the regulation, it may be integrated into your risk-based system with proper planning and integration. The key is to get into your policy and procedure manuals and clearly document how you will be addressing the regulation (staying in compliance) and address risk in your risk program.

Kroon: The risk-management practices of our clients are being driven to higher levels of sophistication by pipeline regulations. Qualitative techniques are being replaced by quantitative assessments. For our company, these changes have created the need for developing quantitative risk assessment tools for external corrosion and alternating current interference.

NACE: Can you provide examples of how a risk-based system is being successfully used in your work -for example, increased pipeline integrity, safety, environmental protection, and cost savings?

Alfano: Once implemented, a risk-management system provides pipeline operators with critical information they can use to operate and maintain their pipeline systems. For example, the output of a successful quantitative risk-assessment should be able to tell you, at any location: 1) the severity of each threat acting on the pipeline, 2) the contributing factors driving each threat, 3) the potential impact to people, places, and the environment due to a loss of containment, and 4) the corresponding aggregate risk level. This risk information, when used as part of a larger risk-management program, can then be directly used to develop targeted response plans. These systems provide a significant improvement in safety, reliability, and optimized spending beyond the ad-hoc decision-making of the past.

Didas: Managing your program using remote monitoring is a successful risk-management practice. You are able to gather the data from rectifiers and critical bonds on a more frequent basis than manual readings. The risk is first recognizing that a reading is in alarm or an abnormal condition and reacting to this reading. The other risk is not visiting these rectifiers and critical bonds except once per year to perform an annual survey and physical rectifier/bond inspection.

Kroon: For 15 years, we have been performing external corrosion direct assessment (ECDA) on hundreds of pipelines. The indirect inspection data and analysis are confirmed by direct examination of the pipe, which leads to calculated corrosion rates. The ECDA data collection and analysis procedures are rigorous and well documented, leading to verifiable condition assessments. We are building an advanced external corrosion risk model that will provide operators with a quantitative assessment of the risk of external corrosion along their pipelines. We are also working to improve our ability to predict the rate of external, galvanic corrosion of steel pipelines based upon soil characteristics.

NACE: Do you have any other comments?

Alfano: Due to ever-changing physical and business environments, a successful risk-management program must be dynamic. For those who are starting down the development of these systems, ensure the success of the development initiative is measured not just on the delivery of the system, but also on the process in place to keep the system current. This will ensure that the benefits achieved through the system will continue to pay dividends through the years ahead.

Didas: I was very luck earlier in my career to work with Kent Muhlbauer and John Zurcher and learn about pipeline risk, codes, and standards from these two gentlemen. They really increased my knowledge and awareness of risk management and its integration into codes and standards. They made my career in the oil and gas pipeline world a better place.

Kroon: Risk-based decision-making is here to stay. Analytical models continue to evolve, requiring real world data inputs. We need to guard against overemphasizing the importance of the model without equally emphasizing the need to collect accurate, reproducible data sets for inputs to the model. Wherever we select a default attribute, we should challenge ourselves to develop a data collection process to better define the condition.

Tony Alfano is a Principal Engineer and head of the Risk Management team at DNV GL. He has an M.S. degree in mechanical engineering and is a Professional Engineer. A member of NACE International, Alfano has more than 10 years of experience supporting clients with risk management focused on pipeline facilities and networks, with an emphasis on transitioning risk-assessment tools into higher-value risk-management programs through model and system development.

Meet the Panelists

Tony Alfano is a Principal Engineer and head of the Risk Management team at DNV GL. He has an M.S. degree in mechanical engineering and is a Professional Engineer. A member of NACE International, Alfano has more than 10 years of experience supporting clients with risk management focused on pipeline facilities and networks, with an emphasis on transitioning risk-assessment tools into higher-value risk-management programs through model and system development.

Jeffrey L. Didas is a Senior Corrosion Engineer with MATCOR, Inc. He has an ASEE degree in industrial electronics from Springfield Technical Community College and BSET degree in electrical/ electronic engineering from Thomas A Edison State College. He has 42 years of experience in corrosion control for oil and gas pipelines, tanks, well casings, and other facilities and industries, both onshore and offshore. His expertise includes cathodic protection, coatings, and internal corrosion. A member of NACE for more than 40 years, Didas has served numerous committees at the association, area, section, and technical levels, including the NACE Board of Directors and NACE Foundation Board as Treasurer. He holds several NACE certifications, including Corrosion Specialist, Cathodic Protection Specialist, and Coating Inspector. He received a NACE Distinguished Service Award and the 2014 R.A. Brannon Award. He is the vice president of NACE for 2017-18.

David H. Kroon, FNACE, is the Chief Technical Officer at Aegion Corp. and former president of Corrpro Companies, Inc. He has a B.S. in chemistry from Yale University and is a Professional Engineer in 13 states. Kroon has more than 45 years of experience in corrosion prevention, including materials performance, protective coatings and linings, pipeline integrity, cathodic protection, and alternating current/direct current interference mitigation. Over his entire career, he has been actively engaged in solving corrosion problems for the energy and water industries. A 44-year member of NACE, he is the recipient of the NACE 2016 R.A. Brannon Award.

Acknowledgement: Pipeline & Gas Journal is grateful to NACE International Editor Gretchen Jacobson for her assistance in preparing this article.

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