Guided Wave Technology

Guided Wave Technology: How It Works, Where To Use It

One of the latest advances in non-destructive testing is Guided Wave Technology (GWT). This method of long-range ultrasonic testing has quickly proven to be invaluable in screening engineering structures, particularly metallic pipelines. The ultrasonic waves can detect cracks and abnormalities in the structure as well as changes in pipeline diameters. This data can then be used to identify areas needing maintenance or repair.

One major advantage of Guided Wave Technology is its ability to screen hundreds of meters of pipeline from a single location, which saves time and money over other methods of screening. Another time-saving feature of this technology is in its automated data collection and recording capabilities. Just one operator can measure and record data using transducers, a laptop, and the appropriate software, even on structures that are difficult to fully access. Furthermore, the technique can be used on pipes that are fully operational. Liquid or gas inside the pipes does not affect the testing so there’s no need to shut down operations to conduct the test.

How Guided Wave Technology Works

Guided Wave Technology works by sending out extremely low frequency ultrasonic waves using a transducer that is attached to the structure or wrapped around the pipe. These waves carry along the structure or pipe and send return echoes back to the transducer. Results are immediately transferred to the software installed on a laptop. Operators can then interpret the results to identify areas of stress, corrosion, internal or external cracks, and changes in the diameter of the pipeline. If any areas of concern are noted, further testing can be done on the spot.

Best Applications For Use

Guide Wave Technology is ideal for long-range inspections of engineering structures or pipelines, particularly those that have limited access or whose size or location limit the use of other techniques. Common applications for use include:

• Soil to Air. Rather than digging up miles of pipeline for routine inspections, GWT can inspect miles of buried pipeline from the soil level down to 40 feet below ground.
• Underground Pipeline Inspections. Pipeline corrosion and stress fractures can be detected using GWT at specified points along the pipe. Since waves can travel up to 40 feet in both directions, inspectors only have to dig up sections of piping every 80 feet. This saves a huge amount of time and reduces the labor demands of excavating and inspecting every foot of pipeline.
• Above Ground Pipeline Inspections. Just because you can see the pipeline doesn’t mean it’s any easier to inspect than underground pipes. Microscopic fractures, internal corrosion, and diameter shrinkage can all be undetected to the naked eye. Guide Wave Technology can inspect up to 400 feet from a single above ground location far quicker and with far more accuracy than any other type of inspection.
• Supports and Insulated Structures. High heights and insulation can limit access to structures. Removing that insulation to conduct an inspection is very labor intensive but it can be avoided using GWT. Likewise, GWT can send out waves for hundreds of feet, limiting the need to physically inspect structures.
• Heater Tubes. Internal and external damage on heater or boiler tubes can be hard to identify, but not with GWT. Single spot scanning eliminates the need for self-propelled instruments that take much longer and cost more per inspection.
• CML/TML. GWT can be used to find areas of corrosion and pitting prior to relocating pipes, preventing costly leaks, fires, or explosions from occurring. Able to detect a 2% or less flaw over hundreds of feet, GWT is a labor-saving technique that pays for itself many times over.

Amerapex is a leader in Guided Wave Technology, using a Magnetostrictive Sensor (MsS) Guided Wave System to conduct inspections. To learn more about Guided Wave Technology from Amerapex visit http://amerapex.wpengine.com/ndt-services/guided-wave/ or contact us at 1-713-263-0900.