Guided wave testing is a form of ultrasonic testing in which the sound waves are sent along the length of a pipe to get information about the condition of the pipe.
The guided wave tool is placed around the pipe and guided waves are sent in both directions along the pipe. They are called guided waves because the sound waves are guided along the length of the pipe by the pipe walls. So, if the pipe is bent, the sound travels around the bend. In conventional Ultrasonic Testing (UT) the sound travels straight, until reflected or refracted. Here tens of meters of piping are examined in one setting. It can examine under insulation or if the pipe is buried. However the tool itself needs to be placed in direct contact with the pipe by removing a short length of insulation.
This method is excellent for corrosion detection in long lengths of pipe, at road crossings and bund penetrations.
Most useful screening of pipe-work for corrosion, both internal and external. The screening will pinpoint areas/lengths of pipe that must be examined by other means (typically conventional UT) to establish the exact amount of remaining wall at the locations where wall loss is detected by the guided waves.
This will cut down greatly on the time (and cost) of determining the integrity of a line using only conventional Ultrasonic Testing (UT). Able to screen lines while in-service. 100% of the line volume is being screened by the guided waves as opposed to UT spot-checking and other external crawler methods which are faced with considerable limitations on coverage.