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Test to predict and against RAPID CRACK PROPAGATION in pvc water pipes

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Plastic Pipe Rapid Crack Propagation Test machine used to predict and against RAPID CRACK PROPAGATION IN PVC WATER PIPES. 


PVC-U water pipes occasionally fail suddenly due to brittle cracks that are several meters long, which propagate along the pipeline at the speed of sound, causing significant water loss. This phenomenon is called Rapid Crack Propagation (RCP). The condition for RCP to occur is when the operating pressure exceeds the critical pressure (PC) and is accompanied by a sudden pressure surge or water hammer action causing cracks. According to the S4 test of ISO 13477, 25 water filled pipe sections measuring 2.42 meters in length and 315 millimeters in diameter were tested at 3 ° C to evaluate the relationship between PC and wall thickness. For pipelines filled with water, thicker pipe walls significantly improve resistance to RCP. 

The residual pipeline extrusion stress has a significant negative impact. A multivariate statistical model and fracture mechanics model have been developed to quantitatively describe these effects and can be used to calculate whether RCP is possible.


What's Pipe Crack Propagation?

The Propagation cracking of plastic pipes refers to the phenomenon where cracks appear on the surface or inside of the pipes due to various reasons during use, and these cracks rapidly propagate along the length direction of the pipes. This phenomenon usually has a serious impact on the structural integrity and safety of pipelines.

Explore the comprehensive crack propagation testing, where we delve into the complexity of state-of-the-art small-scale steady-state testing, commonly referred to as ISO 13477 S4 testing. This method is an important criterion for evaluating resistance to rapid crack propagation, especially in the field of polyethylene (PE) pressure pipelines operating at sub zero temperatures.


The testing program strictly follows the defined standards to control the testing temperature and pressure to reflect real-world conditions. The fluid used in the test reflects the characteristics of the expected application or serves as an equivalent substitute. The internal baffle and external cage play a crucial role in rapidly reducing pressure before slowing down crack propagation, ensuring the controllability of testing conditions. This carefully designed technique achieved steady-state rapid crack propagation (RCP) in short tube specimens, providing a more efficient alternative to full-scale testing. After testing, the inspected pipeline will be carefully examined to determine if cracks have occurred to prevent or propagate. A series of tests conducted at different pressures and constant temperatures enable precise determination of the critical pressure, critical ring stress, and critical temperature of RCP.

Related Standard

ISO 13477 RCP Test of thermoplastics pipes resistance to rapid crack propagation

ISO 13477 standard applicable to the assessment of the performance of thermoplastics pipes intended for the supply of gases or liquids. In the latter case, air can also be present in the pipe.

The test method for resistance to rapid crack propagation of thermoplastic pipes mainly includes small-scale steady-state test (S4 test). This test method specifies a standardized testing procedure in detail, ensuring comparability of test results between different laboratories and improving the reliability and repeatability of test data

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