Exploring the Role and Specializations of NDT Engineers in Subsea Inspections
The phrase "NDE/NDT Engineer" is becoming more common across all sectors of our industry, with little overlap in the description. The goal of this presentation is to describe what an NDT Engineer is, emphasize the educational and experience backgrounds required to become an NDT Engineer, and then go into detail about specializing as a Subsea NDT Engineer. Most current definitions of an NDE Engineer are a combination of an engineer and a qualified NDT Level III, or are misapplied to jobs such as an NDT Level II Technician in some situations. This document intends to not only describe what or who an NDT Engineer is but also to outline the roles and responsibilities of such, as well as the minimal educational and experience qualifications, as well as advanced subsea industry specialty areas in which an NDE Engineer can specialize.
Keywords: NDT, engineer, undersea, inspection, asset integrity, subsea, commercial diving, and ROV are some of the terms used.
What exactly is a Subsea NDT Engineer?
To begin, the term "engineer" appears to have become abused in the industry in recent years. As such, an "engineer" can be a person who operates a train, works on ship engines, designs software or programs computers, connects networks or operates a broadcast, and now also provides custodial services. The majority of these occupations are technical positions that do not necessitate a formal, validated degree in a typical engineering discipline. For the purposes of this paper, engineers, as practitioners of engineering, are professionals who invent, design, analyze, build, and test machines, systems, structures, and materials to meet objectives and requirements while considering practicality, regulation, safety, and cost constraints. In addition, we will take into account graduation from an accredited engineering program, as well as membership and accreditation with a recognized engineering council.
What exactly is a Subsea NDT Engineer?
It is someone who has a BSc or higher in Engineering (or a Science related to engineering), has significant inspection experience with offshore oil and gas and other maritime infrastructure, is proficient in most NDT methods and techniques while also being a subject matter expert in more than one, is accredited by an engineering council and is a member of an internationally recognized organization such as the American Society of Non-Destructive Testing (ASNT), the British Institute of Non-Destructive Testing (BINDT), the Engineering Council (EC), the National Society of Professional Engineers (NSPE), the American Council of Engineering Companies (ACEC), the Order of the Engineer (OE), the American Society of Mechanical Engineers (ASME), or the American Society of Civil Engineers (ASCE).
In addition to the above fundamental technical knowledge, years of experience and "Occupational Knowledge" are required as a basis for becoming an NDT Engineer. This means that an NDT Engineer cannot simply graduate from a university. It necessitates a blend of formal education and on-the-job training.
This practical field experience will include extensive knowledge and familiarity with topside and underwater systems, procedures, damage mechanisms, inspection techniques, and deployment vehicles. Deployment vehicles are merely a means of transporting the tools required to complete a task to the region of interest. Commercial divers, remotely operated vehicles (ROVs), and autonomous vehicles are examples of underwater deployment vehicles. It is not necessary to have formal training as a commercial diver or even an ROV pilot, although it certainly helps! Formal education in material properties, electronic principles, mathematics, chemistry, and corrosion analysis, as well as technical project management, should be required of the Subsea NDT Engineer. Experience and training in Advanced NDT methods such as Electromagnetic Testing, Ultrasonic Testing, Acoustic Emission, Cathodic Protection systems, Computed & Digital Radiography, Guided Wave, and Pipe Inspection Gauge systems (ILI; in-line-inspection) are necessary. Professional certificates such as NDT Level III from the American Society of Non-Destructive Testing (ASNT) or PCN Level III from the British Institute of Non-Destructive Testing (BINDT) will be required. A Subsea NDT Engineer must also be well-versed in regulatory and international standards requirements imposed by organizations such as the American Society of Mechanical Engineers (ASME), the American Petroleum Institute (API), the International Organization for Standardization (ISO), the American Welding Society (AWS), Det Norske Veritas (DNV GL), and others. Professional certifications in welding and pipeline inspection from these organizations are also highly desirable.
An NDT Engineer's job includes knowing both engineering tasks as well as having technical NDT training, on-the-job experience (OJT), and certification. Certification is a documented attestation to one's practical qualifications. A NDT Engineer's primary responsibilities include the interaction of NDT with other engineering activities, the implications of failure, and the contribution of NDT to asset management and life extension. Most system engineers understand why and where their components must be inspected, but not necessarily "how" the inspection should take place or the best potential technique to apply to find the damage mechanisms of interest. That's where the Subject Matter Expert (SME) comes in, and as a fully educated and qualified NDT Technician, you should know how to examine a component properly, but not necessarily why. NDT Engineers are able to bridge the gap between being a competent engineer and subject matter expert. They can use design procedures, such as material selection, to fulfill NDT and construction requirements, as well as undertake root cause analysis, fracture mechanics, and failure analysis, and learn from experience (LFE).
Acquiring experience is essential, but so is putting that experience to use. An NDT Engineer must critically apply knowledge of concepts, principles, and theories of developing technology relevant to the interdisciplinary fields of NDT. An NDT Engineer must have advanced skills in NDT methods substantiating their lead competency role within the subsea sector, but also be able to work in ALL sectors, such as aerospace, nuclear, etc. Analyze engineering challenges by selecting and using mathematical and theoretical data to deliver appropriate NDT solutions while keeping the complete inspection cycle in mind. Finally, apply engineering knowledge to the development, operation, maintenance, and advancement of NDT technology.
Yes, Subsea NDT Engineers also work topside. The great bulk of education, training, and practical experience is gained on land before being adapted for use in underwater or subsea conditions. We know that most of the technology we use in the field of NDT, notably the Ultrasonic and Radiographic methods, initially emerged and were utilized by the medical field before being appropriated and adapted for use in the industrial applications we are more familiar with. The same is true about these technologies being further modified for usage in underwater environments. Most assets in subsea or underwater environments have or are linked to topside components in some way, so complete inspections require the use of both topside and underwater techniques. Offshore platforms, ships, barges, risers, pipes, bridges, docks, berths, above-ground storage tanks, water towers, water intake facilities, amusement parks, hydroelectric dams, and, yes, nuclear reactor pools. The list is endless. Most importantly, one must first understand the technologies and techniques available to them on the surface before attempting to employ them effectively in a more confined and less accessible environment. The majority of underwater work occurs in uncomfortable environments, with little to no visibility, rather than in nice, clear, warm, tropical locales. A Subsea NDT Engineer must be skilled both above and below the waterline.
When thinking of NDT inspection of subsea or underwater assets, offshore oil platforms and pipelines appear to be the first things that come to mind. It is a massive industry, with the Gulf of Mexico alone accounting for more than 80% of all billable underwater commercial diving hours worldwide. The inspections covered by it are not your standard NDT methods. Yes, there are many Visual and Ultrasonic Thickness measurements being performed, as well as underwater Magnetic Particle inspections (although ACFM is taking over), but in these remote locations, particularly in low-visibility or difficult-to-access environments, Advanced NDT methods are gradually taking over. This is also true for the usage of ROVs, where technology is being deployed to eliminate the human aspect, not only for enhanced trust in data collecting but also for reduced human exposure to risky conditions. Technology is advancing quickly these days, so we are seeing an increase in the use of Advanced NDT techniques used underwater such as Automated Ultrasonic Testing (AUT), Shear wave and Phased Array Ultrasonic (PAUT) for full volumetric weld inspections as well as corrosion mapping or crack detection and sizing, Electromagnetic Testing techniques such as Pulsed Eddy Current (PEC) and Alternating Current Field Measurement (ACFM), Computed and Digital Radiography (CR/DR), Cathodic Protection and potential readings (CP), Computed and Digital Radiography (CR/DR), just to name a few.
IMPROVEMENTS IN THE SUBSEA SECTOR
Over the last few decades, there has been a rising need to change the "status quo" of how underwater or subsea assets have been inspected. Underwater assets are "out of sight, and out of mind" for most industries. This is not always the case, but it was for many years. Today, we can see that a shift has begun. Unfortunately, this drive is fueled in part by large disasters that frequently make headlines. However, we will not go into depth about those here.
Subsea assets, by definition, operate in a more invasive and hostile environment, and their failure can have a substantial impact not just on a company's bottom line, but also on the environment in which they operate. This would naturally lead to more frequent monitoring of those assets, as their failure is more costly. Because these assets are in a more hazardous environment, one would assume that such inspections would require a more competent and experienced specialist. This is not always the case; in fact, most of these inspections are assigned to commercial diving organizations, who send out a "jack-of-all-trades" diver to carry out whatever NDT task the Owner requests. Normally, no one would hand an ultrasonic thickness scope to a rock climber and have them climb up their flare tower to take UT thickness readings on a pipeline. Not without the necessary training, documented experience hours, validated qualifications, and current certifications. In contrast, the industry should not put a UT scope in the hands of a diver to do the same thing underwater. Diving, ROV piloting, and rope access certifications are not qualifications that enable effective inspections. They are simply vehicles that transport the qualified and certified inspector to the location of the work. Inspections carried out in this manner are frequently insufficient and do not provide the type of quality data required to accurately assess a system's current condition. Unfortunately, a culture and history of allowing divers with minimal or no NDT training to conduct underwater inspections has developed over the years, without holding them to the same qualification and certification practices required for the same inspection of a topside asset. As subsea inspections are more difficult to execute, and are always in a "confined space" (underwater), on components whose failure would be catastrophic, wouldn't it seem logical to require inspections by specialists who are proficient in the use of those techniques and technologies?
This is a simple example, chosen since it has proven to be the most commonly abused in the past 40 years. Most codes state that ultrasonic thickness measurements cannot be accepted by a unit that only has a digital thickness readout, but must be performed with either a flaw detector or a machine capable of producing an ultrasonic A-Scan in addition to a digital readout (Figure 1). However, until recently, the technology available for hand-held, underwater UT thickness scopes was designed to be confined to a digital thickness display (Figure 2). From a fundamental standpoint, this need makes perfect sense, as all interpretation and sizing must occur from the A-Scan data and interpreting the waveform. We have no means of knowing if the digital thickness reading is accurate and reproducible without an A-Scan display. Is this reading the ID-connected remaining wall thickness of the material or a mid-wall inclusion or lamination? The majority of asset owners would also rely on the contractor providing the service to ensure that the individuals operating the equipment were properly trained and certified. Routinely, this meant simply familiarizing themselves with the UT system, perhaps with a short training course, rather than a full-fledged internal company NDT program complete with written practice, procedures, training, written certification exams, practical demonstrations, etc., proctored by a qualified NDT Level III. Other times, they may invite a topside NDT technician to wave a wand over the diver, magically transforming them into a "NDT Trainee," and then walking them through manipulating the tool while on site. In this way, the actually certified technician can observe the diver on a video monitor, directing them through the inspection procedures, and then sign off on a "job well done". No owner/operator would tolerate such activity on any of their topside assets, so why has it been tolerated for so long underwater?
Figure 1: Diver with UTT scope and A-Scan.
There are no ASNT or BINDT/PCN guidelines or recommendations for underwater NDT inspection personnel training and certification at this time. The Certification Scheme for Weldment Inspection Personnel (CSWIP) is the only organization that currently offers training and certification. Underwater training for Diver Inspectors (3.1u, 3.2u), ROV Inspectors (3.3u), and Underwater Inspection Controllers (3.4u) is included in these schemes. Although this is a good start, these courses only cover the practical use of standard NDT methods such as visual/tactile, ultrasonic thickness, magnetic particles, video/still photography, and cathodic potential readings. Unfortunately, these are not recognized NDT certifications the same as our topside counterparts are required. The transition is underway, and numerous companies are now requiring individuals with these qualifications to perform asset inspections. This pattern will continue, as will the demand for more qualified underwater inspection personnel with advanced inspection training and experience, who hold internationally recognized professional certificates, preferably from a central certification scheme of some kind.
Over the last few years, there have also been more reference guides written and used in an attempt to develop norms for specific sectors of the industry. In 1999, the International Institute of Welding (TIIW) issued a paper titled "Non-Destructive Examination of Underwater Welded Steel Structures" (1).
Despite its simplicity, the information was able to introduce people to the idea that many classic NDT methods may be utilized underwater for the examination of welded steel structures. Many additional papers have since been released with updated information and technologies that we see being used today. To mention a few, "Subsea Pipeline Integrity and Risk Management" (2), "Subsea Inspection Controller" (3), and "Image-Based Damage Assessment for Underwater Inspections" (4). Aside from privately published guidelines or internal procedures drafted by subject matter experts, institutions such as the American Society of Civil Engineers have begun to issue publications such as their "Waterfront Facilities Inspection and Assessment" (5).
So, why are specialized NDT engineers required? The expected answer in today's world is always "SAFETY"! Yes, safety is a factor, but as with most industries, it all boils down to the economic benefits. Hire one individual who can perform the duties of multiple individuals. NDT Engineers bridge the gap between what has to be done and knowing the most feasible and cost-effective approaches to accomplish what's required. Because of their technical understanding of codes and regulations, as well as their experience and competence in advanced inspection technologies and techniques, NDT Engineers can impact greater production output with decreased program costs. Overall inspection durations are reduced by using the most appropriate and efficient inspection techniques to collect the most relevant data. As a result, the probability of detection and the data's dependability and usability improved. Integrating all of the above will boost not only safety but also revenue. More efficient "bottom-time" = maximized "bottom-line"!
Davey, V S, 1999, con-destructive Examination of Underwater Welded Steel Structures, Cambridge, England: Abington
Bai, Yong, and Qiang, 2014, “Subsea Pipeline Assessment for Underwater Inspections,” Gulf Publishing
Clancy, A, 2017. “Subsea Inspection Controller”, #inspector2U
O’Byrne, M, 2018, “Image-Based Damage Assessment for Underwater Inspections”, CRC Press
Waterfront Inspection Task Committee, 201, “Waterfront Facilities Inspection and Assessment”, American Society of Civil Engineers