As pipelines age, a flaw population that varies initially along the pipeline can advance in size and number. Analysis of the serviceability of pipelines based on either in-line inspection or hydrotesting can lead to overly conservative decisions or an excessive risk of failure when the random nature of this population and the pipeline's properties are represented by a "typical" flaw and "average" properties. It follows that decisions on serviceability should reflect the random nature of the variables involved or be justified by demonstrating that the uncertainty in these parameters does not adversely effect cost and safety.

This paper explores the significance of the random variables related to serviceability in pipelines. This study is made under the assumption that continuing serviceability is based on the use of hydrotesting. Results generated via probabilistic analysis form the basis for the discussion of risk and safety and the significance of the random variables. This same technology could be used in (1) risk and safety assessments associated with pipeline operating decisions, (2) designing hydrotests and choosing their frequency to ensure continued safe operation of the line, and (3) assessing the operating and safety implications for flaw populations characterized by in-line inspection.

You can access this article if you purchase or spend a download.