Design to Prevent Long Running Cracks in Plastic Pipe for Water Applications

Rapid Crack Propagation is a material failure mode in which a crack propagates very rapidly over long distances- hence the term RCP. Many years of research have been devoted to studying this phenomenon in various pipe materials to determine the best materials and design methods to prevent the occurrence. Because of its flexibility, ease of joining and long-term durability, along with lower installed cost and lack of corrosion, water companies are increasingly installing plastic pipes. This paper will review the two key RCP test methods that have been developed; the Small-Scale Steady State or S4 test method that is conducted on small pipe samples in a laboratory, and the Full-Scale test method that is conducted on long pipe samples to replicate field conditions. We will then look at the experimental data for selected HDPE and PVC pipes and compare the RCP critical pressure for HDPE and PVC pipe with the pressure rating for the pipe using the standard industry pressure rating equations.