Leak before burst video

This high-speed camera footage shows a notched grey cast iron pipe subject to internal water pressure cyclic loading with a constant amplitude.

At the start of the video the pipe is not leaking. After a few seconds, a leaking crack forms in the notch. This small crack only leaks during the high pressure parts of the subsequent loading cycles. After 10 more load cycles the small crack suddenly grows out of the notch forming a burst. This test was run with relatively high stresses. Other tests suggest that the window between the leak starting and the pipe busting could be longer at lower stresses.

This video shows that leak-before-burst is possible for grey cast iron water pipes subject to a fatigue load, and that the load does not need to change for a leak to develop into a burst.