When dealing with one of the main arteries that distributes natural gas across North America – one in which any outage would be widely felt – maintaining a proactive integrity program is crucial. Large and long pipeline segments, specifically, pose increased challenges when executing effective in-line inspections (ILI), creating the challenge of crafting a solution for the operator that can feasibly produce the necessary data and results.


Understanding the need for an ILI solution starts with comprehending the potential threats that may need to be addressed – cracking, in this particular case. Technologies for in-line crack detection in natural gas pipelines are limited because no liquid couplant is available. Therefore, Electro-Magnetic Acoustic Transducer (EMAT) technology has come into play. Throughout the history of EMAT technology, validation and advancements have taken place. ROSEN first introduced EMAT as an in-line inspection technology in 2010, making continuous developments to address unique operator, or even pipeline, needs.

EMAT is a non-destructive testing technology that has applications in a wide range of industrial sectors. Generally used to assess the condition of manufactured objects, the technology is particularly effective for the detection of stress-corrosion cracking and disbonded coating. EMAT generates an ultrasonic pulse inside a metallic and/or ferromagnetic test object. Because the sound waves are generated in the material, no couplant is needed. Consisting of a magnet and an electrical coil, EMAT uses electro-magnetic forces to introduce sound energy into the test object through a combination of Lorentz force and magnetostriction.


In this particular case, the segment in question is considered a vital piece of infrastructure. This pipeline, at 48” in diameter, transports more than 2.5 billion cubic feet of natural gas per day at operating pressures well over 1000 PSI. Any disruption of operations to the line in question would directly impact the economy. As such, to ensure its safety and reduce any potential impact, an extensive integrity program for the line is critical. It is essential for such a program to manage the integrity of the line using only advanced in-line inspection services, including the use of EMAT for crack detection. Alas, it is not that simple: its large diameter and heavy wall thickness make the line difficult to inspect.

Given these unique conditions, specialized tools were required to inspect the line successfully. At that stage, however, such tools had not yet been developed. In response, ROSEN in 2016 developed a specific EMAT inspection tool, equipping it with a new sensor type and configuration to assist in inspecting this specific line.

Figure 1 – EMAT inspection tool

Figure 1 – EMAT inspection tool


The following year, in 2017, the ROSEN Technology and Research Center (RTRC) in Lingen (Ems), Germany, proposed the development of yet another EMAT-technology enhancement. The improved technology would leverage artificial intelligence (AI) and machine learning (ML) to enable the utilization of a different sensor, one that is typically used for lower-wall-thickness applications. Additionally, the alternative sensor is known to be less susceptible to acoustic noise when the wall thickness is high. The proposed developments resulted in the operator hiring ROSEN to pursue these technology improvements and develop the heavy-wall EMAT tool. The development of the tool took three years. In addition to the testing that is essential to the development of any new tool, it also underwent extensive operator-supported testing and evaluation. In fact, the operator required their Technology Qualification Process to be completed prior to use – an extensive process that included:

  • Proof of concept
  • Performance qualification
  • Pilot testing
  • Performance validation
  • Performance tracking


The first inspection using the new technology took place in early 2021. Over the course of the year, two additional inspections were completed using the same tool. Since then, a new smaller-diameter version utilizing the same technology has been created. ROSEN’s Data Evaluation group has completed its first reports from these inspections. Field verification of the submitted results are now underway, and the results from the field will provide valuable information to aid in gaining greater knowledge for a better understanding of the initial results and tool capabilities.


The ability to innovate and create solutions that are tailored to a specific situation is imperative when it comes to tackling difficult lines and operating conditions. A strong vendor/operator relationship creates an environment of collaboration that empowers our international team from ROSEN locations all across the globe to work together with the aim of developing the optimal solution for each challenge.