局部減肉形状による炭素鋼配管の破裂圧力評価への影響 Geometrical Effects for Burst Pressure Assessment on Carbon Steel Pipe with Different Local Metal Loss Types Based on the API/ASME FFS Code

Fitness-for-service (FFS) assessments are quantitative engineering evaluations that perform to demonstrate the structural integrity of an in-service component that may contain a flaw or damage. It can be used to make run-repair-replace decisions to help determine if pressurized equipment containing flaw that have been identified by inspection can continue to operate safely for some period of time. <br>This paper provides a burst pressure assessment on carbon steel pipe with different local metal loss types based on the Level 3 assessment of API⁄ASME FFS code. The Level 3 assessment is a computational method (e. g. FEM: Finite Element Method) described in ANNEX B in API-579-1⁄ASME FFS-1. As stated therein, evaluations of plastic collapse (B 1. 2) and local failure (B 1. 3) are required to be performed for the assessment of metal loss. <br>The author calculated the Maximum Allowable Working Pressure (MAWP) inside a cylindrical shell with local metal loss by the criteria of both plastic collapse and local failure. And the results of safety margin are also discussed in this paper.