A methodology is presented for Level 1 and 2 Fitness-for-Service (FFS) assessments of process and power piping subject to random vibration loading. The intent is to provide a basis for random vibration assessment based on concepts from spectral fatigue, which is simplified to the degree that a non-specialist can conduct the FFS assessment with little prior knowledge of the subject matter. The proposed Level 1 FFS assessment is based on extension and generalization of established industry screening curves for piping vibration. The measured (overall) RMS vibration level is compared against allowable values given by the curves evaluated at the average crossing frequency of the measured vibration. The proposed Level 2 FFS assessment utilizes an allowable cyclic stress. The allowable stress is a function of the target design life as well as the average crossing frequency and kurtosis of the measured vibration. Both approaches are illustrated by example.
Pipes, Random vibration, Fitness-for-service
Breaux, L., McNeill, S. and Szasz, G., “Fitness for Service Assessment of Piping Subject to Random Vibration,” Proceedings of the Pressure Vessels and Piping Conference 2016 (PVP2016-63695), Vancouver, Canada July 2016.