Prevent Pipeline Failures by Ultrasonic Inspection  


Pipelines play an extremely critical role in our lives. We all know how households use pipelines to ensure round the clock supply of water. However, a much more important application of pipelines is for the transportation of industrial liquids and gases over a long distance. From the pharmaceutical industry to the food and beverage sector, pipelines are considered to be an integral; part of the production process. Regardless of how they are used, pipelines often remain buried underground, and therefore, suffer from neglect and lack of maintenance. Corrosion-related defects can lead to many different types of pipeline failures, including leaks, decreased structural integrity, and loss of containment.  

While pipeline defects can be detected in many different ways, the most efficient one is perhaps the ultrasonic inspection method. This advanced technology has now become an integral part of management and quality control for any asset owner. The term ultrasonic describes sound waves with higher frequencies compared to human hearing’s audible limit. Ultrasonic waves are used to generate important data that can be analysed to understand the condition of pipelines and implement corrective measures. 

Typical components of an ultrasonic pipeline detection unit comprise a receiver, a display device, and an ultrasonic transducer. When sound waves travel through solid, liquid, or gaseous media, they encounter different boundaries, resulting in certain portions of the waves getting reflected back to a receiver. This is the underlying principle of pipeline flaw detection using ultrasonic detection. The receiver or the pulser generates high-voltage electrical pulses and its voltage powers the transducer so that high-frequency ultrasonic wave energy can be created.  

While propagating through different boundaries, the sound produced by the transducer encounters different boundaries or anomalies. This is when a part of it gets reflected back to the receiver. Then the transducer converts the reflected sound wave to an electrical signal and shows it on the display screen.   

Understanding the Methodology  

Straight beam testing and angle beam testing are the most commonly used methods for ultrasonic inspection of pipelines. Defects that are parallel to the object’s surface are identified by straight beam testing.  This methodology is also perfectly suited for identifying porous areas and voids. In this method, the transducer is coupled by the operator to the test piece, and ultrasonic waves are sent through the structure. The next step is the identification and sorting of the echoes returning from the pipe’s back wall from those arriving ahead of the same. Cracks or other discontinuities are indicated by significant signal echoes arriving before the back wall.  

As implied by its name, angle beam testing helps locate pipeline defects that are tilted with reference to the pipeline’s longitudinal axis. Such defects are typically found in structural metal components and welds. This technique uses an immersion transducer or a common angle beam transducer at the appropriate inclination for the emission of sound waves.  

Benefits of Ultrasonic Inspection 

The most noteworthy benefit of ultrasonic inspection is its versatility and speed compared to other methods. Some other important benefits include  

  • Higher sensitivity to surface and subsurface defects 
  • Higher depth of penetration compared to other non-destructive testing (NDT) methods. 
  •  Ideal for pipelines that are difficult to access. 
  • Can be mobilised and deployed quickly because it requires minimal part preparation. 
  • Provides almost instantaneous results. 

If you want to find out more about the ultrasonic inspection of pipelines, please contact the expert technicians at Austeck.