Frans Scholten, Ernst van der Stok, Jan Breen
Papers # 2014 Chicago
Very occasionally PVC-U water pipes suddenly fail due to a long brittle crack with a length of many meters which propagates with the speed of sound along the pipe and causes extensive water loss. This phenomenon has been recognized as Rapid Crack Propagation (RCP). The conditions under which RCP can occur are an operating pressure above the Critical Pressure (PC) combined with a sudden pressure surge or water hammer which initiates the crack. S4 tests in accordance withISO 13477 on 25 pieces of 2.42 m long, 315 mm water-filled pipe segments were performed at 3 °C to assess how PC depends on the wall thickness. For water-filled PVC pipes a thicker pipe wall clearly increases the resistance to RCP. Residual pipe extrusion stress has a distinct negative influence. A Multivariate StatisticsModeland a Fracture Mechanics Model were developed which support these findings.