Test to RAPID CRACK PROPAGATION – CRITICAL PRESSURE for PIPE.  

Determination of resistance to rapid crack propagation (RCP) according to ISO 13477 (S4-test). 

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.

UnitedTest supply 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.

Testing machine used: 

UnitedTest UT2039 series Plastic Pipe RCP test, Thermoplastics pipes for rapid crack propagation test machine.

For more information or details, please contact us:

Email: export@unitedtest.com 

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