Example 2: Pipe Support Having a Small Pipe on Concrete Block
The following figure shows inspection report plot (top graph), a photo of pipe support (the left bottom), and amplified plot of pipe support signal (the right bottom). The big pipe is supported by a small diameter pipe on concrete block. The signal from a pipe support is shown at 32 and 128 kHz. But the pipe support signal at 128 kHz does not show because the guided wave signal at high frequency does not interact well with an attachment. If there is no defect in pipe support, no signal is reflected from it. Therefore, 128-kHz signal is much easier than low-frequency signal in finding defect in pipe support.