Section 4. Ageing and Life Extention of Pipelines: Introduction

This section addresses issues associated with degradation, life extension and reuse of pipelines. In addition, one paper in the section addresses an issue related to leak potential of an LNG flare header due to temperature gradient and another paper addresses integrity assessment of pressure vessels. Regarding pipelines, there three main aspects that affect their ageing assessment and life extension studies. These are: 1) time dependent materials degradation such as corrosion and fatigue, 2) changes in operational conditions particularly fluid composition, and 3) accidental damage such as drop object impact. Maintaining safe operating condition of pipelines, particularly those handling corrosive fluids requires implementation of proper corrosion control strategy that includes inspection and maintenance programs to avoid uneconomical decisions if inspection and maintenance are scheduled too early, and to ensure against increasing the probability of failure leading to unacceptable risk if the inspection and maintenance is scheduled too late. The papers in this section highlight the importance of in-line inspection as well as requalification in case of change of operating conditions.