Engineering Critical Assessment of Offshore Pipelines under Operational Loading Phase According to BS 7910 Guideline

Offshore pipelines are an efficient long-distance transportation method for oil and gas. These are usually constructed by the use of girth welds, while welds may naturally contain flaws. Hence, it is essential to inspect the fracture response of girth welds in order to check the structural integrity of the pipeline. One of the guidelines that is using wide spread for investigating the fracture response of steel structures is BS 7910 which is based on Engineering Critical Assessment (ECA) method. In this paper Engineering Critical Assessment (ECA) of offshore pipeline girth welds is done according to BS 7910 through Crackwise software and the influence of several parameters on ECA is presented. It is concluded that Influence of misalignment on axial internal surface flaws is more significant than on axial external flaws. Furthermore it is observed that internal surface flaws have always larger values for tolerable defect heights than external surface cracks. In addition, circumferential surface flaws have evermore larger amount of acceptance level in defect heights than axial flaws.