L51445 Investigative Procedures for Examination of Failures in the Field

The ability to conduct a failure investigation depends on the quantity and quality of the evidence collected in the field. If, for example, the samples or evidence containing the origin or origins is not located in the field and taken into the laboratory, it is not possible to determine the probable cause. The need exists for a standardized recommended practice for pipeline failure data gathering. The purpose of this report is to describe the procedures used in conducting the field examination portion of a failure investigation, to provide a basis for the selection of samples, and outline information that may be helpful in determining the cause of a failure. When confronted with a number of feet of broken twisted pipe strewn along a pipeline right-of-way, it can seem like an impossibility to reconstruct what caused a failure. Yet in several hundred investigations that have been conducted by the authors, the causes have been established. The field portion of the investigation has been divided into four steps: (1) Survey the failure site and fracture to define the nature of the fracture, (2) Locate the fracture origin or origins, (3) Estimate the probable cause, and (4) Select appropriate samples for detailed laboratory examination. The procedure described herein is suggested for guidance in conducting the field-examination phase of failure investigations. It may not be necessary for all failures and, in some cases, additional information and steps may have to be implemented depending upon the specific suspected cause. The authors believe the procedure presented will be useful and serve as a building block.