How to deal with older pipelines

摘要

Gasunie operates 1600 km (1000 miles) of high pressure transmission pipeline that was already constructed in the 60s, according to the specifications of that time. However, that means that they do not always fulfil the more stringent present day toughness requirements. This discrepancy makes it necessary to analyse how to deal with old pipelines. That analysis is given in this paper. Firstly a large database with all available information about mechanical properties and chemical compositions has been compiled. Then these data have been evaluated and the fracture properties for both initiation and crack arrest have been established. Based on this evaluation risk analysis studied have been performed.