Abstract
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.
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.
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.
