A Data Driven, Risk Based Approach to Manage Small Bore Connection Vibration Fatigue Failures on Process Plant

Abstract The risk of vibration-induced fatigue failure of process piping includes loss of containment in hydrocarbon and other critical systems. This can have safety, reliability and regulatory consequences. Vibration-induced fatigue accounts for more than 20% of process piping failures 1. Operator experience indicates that most of these failures occur on small bore connections. Commonly owners of process facilities employ a reactive approach to tackling these issues through troubleshooting efforts once an issue has been identified, ie a “fail-then-fix” approach. The Energy Institute (EI) “Guidelines for the Avoidance of Vibration Induced Fatigue Failure 2nd Edition” (AVIFF) 1 lays out a semi-quantitative analysis based approach to assessing piping and small bore connections in a pro-active manner. However, this approach can be impractical to implement on larger, mature facilities as requires detailed as-built process conditions and piping layout to be collated. Conversely applying mechanical bracing in the form of clamps or conducting vibration monitoring on all connections across all process conditions is impractical. A data driven, risk-based approach combining aspects of the EI AVIFF Guidelines together with vibration surveys and best practice assessments was developed and executed for four large refineries. This paper describes the approach developed as well as sample statistics from the findings that can be used by other owners to consider and plan similar programs. The paper also considers how to risk rank and prioritize, considering complexity and type of issue as well as identifies assessment limitations and risks outstanding to maximize risk reduction for the given program expenditure.