Long-Term Performance of Pipeline Renewal Liners

It has been proven and well documented during the past thirty (30) years that plastic pipe material, i.e. thermoset and thermoplastic resins, have a stress regression characteristic. Early testing for the Plastic Pipe Institute during the 1960's by several recognized laboratories developed stress regression values for various plastics. This testing procedure is now characterized in ASTM D 2837 for thermoplastic resin pipe. This was subsequently completed by various laboratories for thermosetting resin pipe and is characterized in ASTM D 2992 testing standard. Testing for external pressure for an unconfirmed specimen is provided in ASTM D 2924. Testing for external pressure for a circumferentially confined specimen has been completed, in part, by the Trenchless Technology Center, Louisiana Tech University, Tulane University and others. An ASTM test procedure is currently being developed for confined liners in an external pressure environment.