Potential Failure Modes Analysis
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| Damage caused by dam failure in Iowa.
(Image Source: FEMA) |
“Potential failure modes are mechanisms that can result in an uncontrolled release of the reservoir. A potential failure modes analysis is a critical first step in conducting a risk analysis. It requires a detailed records review and a review of dam performance (e.g., instrumentation, visual, and operational). Information is also needed on flood and earthquake frequencies in order to consider hydrologic and seismic potential failure modes. The perspective of local office personnel, including dam operators, inspectors, and dam tenders, is invaluable. The goal of a potential failure modes analysis is to: (1) identify the site-specific credible potential failure modes for a given dam; (2) provide complete descriptions of the potential failure modes, including the initiating event and the progression of steps leading to an uncontrolled release of the reservoir; and (3) provide a general description of the magnitude of the breach, including identifying and recording the factors that make the potential failure more likely and less likely and the consequences more severe or less severe”.[1]
“It is recognized that large controlled flood releases may result in significant downstream consequences, including loss of life, but these events have typically not been included as potential failure modes because they result from intended operation of the dam. Large controlled releases that may result in serious downstream consequences are typically made to prevent even greater consequences that would occur from dam failure. Agencies may elect to consider the risk from large controlled releases, and risk communications should occur when large releases are made”.[1]
Potential Failure Modes Analysis (PFMA) can be a useful tool during the design process to confirm that all potential failure modes are properly identified and addressed in the design. This is true for both the design of new dams and the modification or repair of existing structures.
Best Practices Resources
Best Practices in Dam and Levee Safety Risk Analysis, USACE/USBR
Risk-Informed Decision Making (RIDM) Interim Policy Guidance, FERC
Trainings
On-Demand Webinar: Application of PFMA in Dam Safety
On-Demand Webinar: Potential Failure Mode Analysis as a Dam Safety Tool Part I: Introduction to PFMA
Citations:
Revision ID: 7400
Revision Date: 07/21/2023