Ultrasonic Metal Loss Inline Inspection

Ultrasonic Metal Loss Inline Inspection

  • avatarDexon Technology
27 October 2023

The Advantages of Ultrasonic Metal Loss In-line Inspection: Precision and Versatility

In-line inspection techniques play a pivotal role in ensuring the safety and integrity of pipelines used in various industries. Among these techniques, pulse-echo ultrasound stands out for its precision and versatility. In this article, we will explore the advantages of using ultrasonic inline inspection over other methods and highlight its impact on direct measurement, Probability of Detection (POD), increased accuracy of international engineering standards, applicability to different materials, and the ability to detect and size a wide range of anomalies.

For a comprehensive overview of Dexon Technology PLC’s metal loss in-line inspection program click here to download the brochure.

Direct Measurement

One of the standout advantages of ultrasonic inline inspection is its ability to provide direct measurements of pipeline conditions. Using pulse-echo ultrasound, hundreds of thousands of measurements per square meter of pipe wall can be collected. This level of granularity allows for detailed wall thickness measurements with an astonishing accuracy of down to 0.3 mm in through-wall height. Individual A-scan ultrasonic measurements are recorded, offering an unparalleled level of insight into the condition of the pipeline.

Probability of Detection (POD)

POD is a critical metric for assessing the reliability of inspection techniques. Ultrasonic inline inspection excels in this regard, offering varying sampling resolutions with customizable axial and circumferential sampling resolutions to meet specific inspection data and assessment requirements. Some providers, such as Dexon, offer ultrasonic inspection resolutions as low as 1 mm x 1 mm, resulting in an impressive POD of 1 mm at 90% certainty. This high POD ensures that anomalies are reliably detected, minimizing the risk of false negatives.

Improved Accuracy of International Engineering Calculations

The use of international engineering assessment calculations is crucial for pipeline operators to ensure the safety and integrity of assets. Ultrasonic inline inspection sets itself apart by providing highly accurate input data, which leads to more precise assessment results. This accuracy is particularly beneficial when adhering to standards such as API 579, ASME B31G, POF 100 2021, and RSTRENG. These standards demand a high degree of accuracy in assessment, and ultrasonic inspection techniques rise to the occasion, resulting in more accurate pressure calculations and reliable maintenance and repair recommendations.

Inspection of All Materials

Versatility is a hallmark of ultrasonic inline inspection. Unlike some other inspection methods, ultrasonic techniques allow for the inspection of both ferrous and non-ferrous materials. This includes materials such as carbon steel, high-density polyethylene (HDPE), and stainless steel. The ability to inspect a wide range of materials makes it a versatile choice for pipelines in various industries.

Accurate Detection and Sizing of Anomalies

Ultrasonic inline inspection offers precise detection and sizing capabilities for a wide range of anomalies, including metal loss and geometric irregularities. Metal loss detection and sizing are available down to an astonishingly detailed resolutions of 1 mm x 1 mm at 90% certainty, ensuring that even small anomalies are not overlooked. Additionally, pulse-echo ultrasound allows for the assessment of pipeline ovality, which can significantly impact a pipeline’s efficiency and profitability.

Furthermore, ultrasonic inspection provides pipeline feature detection and identification services along with 3D mapping capabilities. This is particularly valuable for older pipelines with missing or inaccurate construction records. Ultrasonic inline inspection can restore accurate as-built plans with location mapping for underground and subsea pipelines, providing a comprehensive assessment of a pipeline’s physical characteristics.


Ultrasonic inline inspection offers a compelling array of advantages that make it a preferred choice for pipeline integrity assessment. Its ability to provide direct measurements with remarkable accuracy, high probability of detection, adherence to international engineering standards, applicability to various materials, and precise detection and sizing of anomalies make it an indispensable tool for ensuring the safety, reliability, and efficiency of pipelines across industries. As technology continues to advance, ultrasonic inline inspection will undoubtedly remain at the forefront of pipeline integrity management.