Most pipeline companies operate infrastructure that spans a wide range of vintages including pipelines that were built in 1950s to the 2000s. Some of the pipelines have changed hands, and in many cases, more than once, resulting in a loss of the operating history and of pertinent pipeline data relating to the grade or mechanical properties. In the case of pipelines of unknown grades, PHMSA (OPS/DOT) stipulates the assumption of a 24 ksi yield strength, regardless of its construction. OPS also allows the establishment of the Specified Minimum Yield Strength (SMYS) of the pipeline by verifying its...
Most pipeline companies operate infrastructure that spans a wide range of vintages including pipelines that were built in 1950s to the 2000s. Some of the pipelines have changed hands, and in many cases, more than once, resulting in a loss of the operating history and of pertinent pipeline data relating to the grade or mechanical properties. In the case of pipelines of unknown grades, PHMSA (OPS/DOT) stipulates the assumption of a 24 ksi yield strength, regardless of its construction. OPS also allows the establishment of the Specified Minimum Yield Strength (SMYS) of the pipeline by verifying its yield strength by carrying out statistically valid sampling. Conventional tensile testing requires the removal of samples from the pipeline for testing which results in temporary line shut down and loss of transmission service. The constructability issues around this are complex, and it requires line repair after sample extraction. In addition, this can result in a loss of throughput and consequent disruption of supply. An appropriate and relevant amount of data from the nondestructive Automated Ball Indentation (ABI) tests and the destructive tensile and fracture toughness tests provides reasonable statistical data sets to establish the validity and accuracy of the ABI technique which produces both tensile and fracture toughness properties from each single test. The ABI test (accomplished in less than two minutes) is now proven to replace both the tensile and fracture toughness tests without specimen machining or service interruption, and it requires only localized surface polishing of in-service pipelines.