Case History: HDPE Pipe Boot Failure Due to Thermal Contraction of HDPE Pipe: Fid-Bau Portal

Case History: HDPE Pipe Boot Failure Due to Thermal Contraction of HDPE Pipe

Padovani, A.C. / Minch, M.J. / Hunt, C.E.

High-density polyethylene (HDPE) pipe boots are typical in landfill construction where leachate collection pipes need to be extended from within containment areas, towards storage ponds, tanks, or treatment facilities located outside of the containment system. The installation of a pipe boot creates a fixed point for the pipe at the location of the penetration. The remaining length of the attached pipes, which can be subject to thermal expansion and contraction cycles, can range from several hundred to thousands of meters. For typical pipe lengths, the potential deformation due to expansion and contraction can vary between several centimeters to several meters, depending on changes in temperature and length of exposed pipe. For this case history, a large temperature differential combined with over one hundred meters of unrestricted length of pipe led to an observed permanent pipe deformation of approximately 0.25 meters. The resulting tensile stress was responsible for the failure of the pipe boot at the end of the pipe alignment and subsequent release of fluid outside the containment area. To account for the potential for pipes to undergo expansion and contraction deformations during construction, several measures are recommended during the design process: (1) verification of expansion and contraction potential of exposed pipes based on expected temperatures during, and after, construction and length of pipes, (2) specifying pipe construction sequence in the construction documents to reduce pipe movements during construction, and (3) boot designs that include a flexible connection to allow pipe movements to be isolated from the boot itself.