Decompression wave speed and crack velocity measurements during S4 test in water pressurized plastic pipes: Part 2. Criteria for onset of rapid crack propagation

It was shown that this critical crack velocity is always greater than the theoretical decompression wave speed in water filled pipes. Until now, the criterion for rapid crack propagation in S4 was understood to only involve the former condition in water pipes. With this and the latter condition proposed, more complete criteria for rapid crack propagation in water filled plastic pipes using the S4 method is now established.