Pipelines can be exposed to external interference resulting in damage in the form of dents, cracks and notches. Such damage may reduce the capacity of the pipeline, and for further safe operation of the pipeline a reliable evaluation of the defects are of importance. At present several assessment methods are available, but there is a need to evaluate these methods against test results. DNV performed 14 tests on dented pipes between 1979–1981, sponsored by several oil and gas companies. The tests included pure dents, the combination of dent and notch, and also the effect of repair of the notch by grinding. This paper presents those test results. The test results are used in a JIP project with the objective to develop a Defect Assessment Manual for pipelines, conducted by Andrew Palmer & Associates, DNV and several other organisations, (Cosham, Kirkwood, 2000) DNV finds it beneficial for the industry as a whole that the results obtained from the tests are published and made available, and has therefor decided to publish the background information and the test results.
Damage in the form of dents, cracks and notches can significantly reduce the pressure containment capacity of a pipe in order to be able to develop and validate potential future capacity criteria test data is of importance. By presenting the test results the industry can compare and validate the various criterion against these results. A total of 14 full-scale burst tests with pipes containing pure dents, dents and notch, and the notch ground were carried out. The tests were conducted as a Joint Industry Project to investigate the residual strength of damaged pipelines and risers. Large diameter pipelines were used in the tests, where 9 of the tests were carried out on 814ram (32") diameter pipes and 5 on 273mm (10") diameter pipes.
