Refined product consumption is on the rise: for example, demand of oil rose by 1.7% in 2017, likely driven by the transport and petrochemical sectors. That being said, the production of refined oil also grew, by 1.4%. To put it bluntly, the world’s energy consumption increased by 2.3% in 2017, and the production of energy is barely keeping up with a rise of 2.4% (“World Energy Statistics | Enerdata”). Refining facilities are under pressure to perform efficiently and safely. Ensuring the integrity of refineries is more vital than ever, and inspecting piping is part of protecting their core.

The need for integrity assessments that give insight into the state of a refining asset is not solely driven by the need to produce but also by other factors, including:

  • Refinery location – refineries are often located close to waterways or major cities, for various reasons, including the transport of the un-refined product to the facility and, in turn, the transport to the consumer (, 2019).
  • An increasingly more stringent regulatory environment.
  • The public’s awareness and stake in topics like climate and pollution.
  • Change-of-ownership situations can cause gaps in integrity status knowledge of various assets within the refinery.

One solution to battle the increasing needs of energy demand and the public’s awareness is the most efficient operation of a refinery. Small pipes, usually between two and twelve inches in diameter, zig-zag through refineries to transport different types of product to different stages in the refinery process, be it raw product entering the facility, already refined product on its way to be stored or to the consumer, or waste ready for proper disposal. To put it in perspective, a refinery with a throughput of 400,000 barrels a day encompasses approximately 160,000 km of piping – that is a lot (“Shell Pernis”). Regular maintenance and inspection allows for reliable operation. Inspection can take place independent of the refinery’s, or any given pipe’s, operational status, meaning no shutdown is necessary. Alternatively, given the sheer amount of piping within a facility, inspections can be scheduled, if need be, during or before shutdown periods. Flexibility is key. Inspections are non-intrusive and allow operators to know what repairs are needed prior to the next scheduled turnaround.


Given the different types of piping available in a refinery, different solutions are required. At ROSEN, the techniques available range from non-destructive testing methods, traditional free-swimming in-line inspection tools (ILI) and ILI solutions used for piping deemed “unpiggable,” meaning they have complex designs and challenging operating conditions, and the medium transported often has unique characteristics. Threats to piping include all of the most common threats: corrosion, cracking, geometry features, etc. Typical piping configurations found in refineries, which present unique inspection needs, are shown in Figure 1.

Figure 1: Different piping configurations present varying types of threats, and inspections are conducted using different techniques.


As always, every pipe configuration is different and presents unique challenges and conditions. Ensuring proper inspection requires finding the best approach, considering all factors. There are, of course, a variety of solutions, each suitable for varying assets. Some of the available technologies and their applications are outlined here.

In-field service equipment – for a complete picture all the way around the pipe
In-field service equipment (IFSE) is a set of manually operated devices ideal for inspecting above ground piping from the outside while still gaining integrity data of the interior and exterior of the pipe wall. It is also used for the inspection of piping at supports or hangers to detect corrosion or corrosion scabs, which is localized corrosion occurring on the exterior of the pipe underneath coating or paint, causing the location to slightly bulge. The equipment has two different set-ups: circumferentially orientated (CIRC) and axial orientated (AXUS). It uses electromagnetic acoustic transducer technology (EMAT) that induces a soundwave into the pipe wall. The technology provides many different wave modes to inspect a structure, each with unique characteristics with their own specific application for optimal feature detection. The circumferential inspection is performed rather quickly as the CIRC tool travels along the entire length of the pipe, sending the EMAT signal through the entire circumference of the line.

Figure 2: CIRC (left) and AXUS (right) are ideal for the entire inspection of pipe body including at supports or hangers.

The AXUS tool follows, visualizing any anomaly by sending a high-frequency wave in an axial direction in search of an echo from the feature itself. The AXUS tool is directed around the circumference of the pipe to provide a complete image. These technologies are ideal for detecting the most natural occurring feature – corrosion. The CIRC tool provides an axial profile of the corrosion, and the AXUS tool adds the circumferential extent of corrosion as well as some axial distance information. Combining both techniques allows for integrity status on both pipe body and possible corrosion under external pipe supports.

Long range ultrasonic testing – no access, no problem
Long range ultrasonic testing (LRUT) is ideal for inspecting piping with limited accessibility, such as buried pipe at road crossings, where the pipe’s path inside a refining facility physically dips underneath a road (or other facility infrastructure) and continues on the other side, or insulated and above ground piping. LRUT technologies allow low-frequency guided ultrasonic bulk wave transmissions to propagate into the pipe from a transducer array fixed around the pipe; the technology operates just above audible frequencies. These low frequencies are necessary to enable an appropriate wave mode to travel the surface of the pipe.

Figure 3 shows the LRUT collar on the pipe, ideal for inspecting piping with limited accessibility.

The guided waves can travel many meters and are therefore used to test large areas from a single point. Any changes in the thickness of the pipe – on either the interior or the exterior wall – cause reflections that are detected by the transducer array wrapped around the pipe. The system enables a trained operator to discriminate between metal loss and pipe features – welds, in particular.

Linear array ultrasonic testing – taking the risk out of heat-affected areas
Heat-affected areas are zones where the microstructure and properties of the pipe have been altered by welding or heat-intensive cutting. The heat from the welding process and subsequent cooling can increase sensitivity at these locations. These unique and high-risk areas can be inspected using an advanced method of ultrasonic testing referred to as Linear Array Ultrasonic Testing (LAUT). This technology uses an array of UT probes consisting of many small ultrasonic transducers, each of which can be pulsed independently. Pitting, a unique form of corrosion that refers to features smaller than 2 mm, cannot be reliably detected by conventional UT methods, simply because the size of the defect is too small compared to the area inspected. LAUT techniques accomplish the needed precision and get great coverage quickly.

In-line Inspection
Not only external non-destructive testing is used to inspect piping in refineries, but free-swimming in-line inspection tools are also capable of inspecting insulated and buried piping. These inspections, however, can be faced with a combination of various challenges, which may rule out the possibility of using traditional methods. These challenges can include but are not limited to:

  • Small diameter piping
  • Low flow or pressure rates
  • Complex piping design
  • Single access points
  • Characteristics of the medium

The Challenging Pipeline Diagnostics Division of the ROSEN Group makes the in-line inspection of challenging assets their daily business. Over the years, we have learned that each pipe is unique; however, building a specific tool for every inspection is not feasible. Therefore, the ROSEN Toolbox approach was developed, which incorporates complementary units, such as technologies, methods and market knowledge, to enable our solution experts to optimally address each challenge. By utilizing these tailored solutions, which are equipped with proven technology from the ROSEN portfolio, the challenges that present themselves in the in-line inspection of refinery piping can be overcome, and the necessary high-quality data on the asset’s integrity can be collected.


Data collection has been a fundamental component of integrity management programs since the advent of intelligent inspection methods. As echoed in global trends around data mining and “big-data” approaches, many organizations are now beginning to “collect everything.” We can see this reflected in the new generation of mobile Field Data Capture tools, RFID tags enabling tracking of specific items and the wider “digital transformation” processes currently underway in most organizations.

Data Management
Between the various inspection possibilities – be it in-line inspection or external NDT methods – data collection is the key goal. But what then? What to do with the valuable data gained? In order to facilitate the extraction of maximum business value from these and all other kinds of data, the first component is a comprehensive data management strategy. What is required is a strategy that allows various parts of the business to have access to the data that each requires, and one that facilitates the integration of this data with (potentially all other) existing or new data. It is only through integrated Data Management strategies that truly data-driven insights can be derived and can lead to more informed decision processes around repair planning, remediation or other risk-reduction activities. Really enabling the latest generation of machine learning models and other emerging AI-based techniques also requires transparent Data Governance policies and processes in order to implement and support the operation of the organization’s data management strategy.

Data Governance
Whether the final aim is to keep inspection or survey data in-house or to utilize the various cloud-based solutions that offer extendibility as data sizes continue to grow, clear organizational goals, aims and responsibilities should be documented as part of Data Governance. Within such strategies, the spatial dimension cannot be overlooked: we have seen the recent arrival of commoditized software functionality, which provides time awareness, meaning historical (inspection) data can be matched with the relevant state of piping.

Integrated Systems
The software and systems-related options available to operators have moved far beyond classic Excel sheets and tables to hybrid spatial platforms and big data storage solutions that for example allow spatial, linear and engineering measures to live together in one version of the network. These systems, of course, include data and integrity management strategies gained for piping in refineries.


Rutger van Kampen, global head of the Non-Destructive Testing business line at ROSEN, comments on what the industry needs in terms of perfecting the integrity management of piping in refineries:

As the demand for energy does not waver, the need for efficiency, reliability, and most importantly, safety will continue. That includes the integrity management of piping. Comprehensive care for any asset needs to move towards more of a 24/7, all-over kind of model, where operators can constantly monitor, perfect and adapt all aspects of their assets. As technology continues to advance and our experience with making the most of massive amounts of data grows, we see the future becoming more autonomous. Drivers for this are of course as vital as safety and as pragmatic as cost saving. The tightknit network of piping in refineries often creates physical accessibility challenges for inspection tools and on-site personnel, which in turn can create unsafe environments and high costs for temporary scaffolding or launching and receiving equipment. The obvious next step is to eliminate those challenges with technology capable of finding its own way around, be it robotic crawlers or other self-propelled devices. In terms of data, big steps have already been taken in managing the data itself. However, machine learning and artificial intelligence models also will offer not only better decision support to operators, they will also allow for predictions to be made, making it possible to get ahead of any threats that may present themselves and mitigating them accordingly.

References: “World Energy Statistics | Enerdata.” Yearbook.Enerdata.Net, 2019, Accessed 13 Mar 2019.
Neb-One.Gc.Ca, 2019, Accessed 13 Mar 2019.
“Shell Pernis.” Shell.Nl, 2019, Accessed May 4, 2019.