Resources - System Safety

Failure Modes and Effects Analysis (FMEA)

FMEA is a qualitative reasoning approach best suited for reviews of mechanical and electrical hardware systems. The FMEA technique (1) considers how the failure modes of each system component can result in system performance problems and (2) ensures that appropriate safeguards against such problems are in place. A quantitative version of FMEA is known as failure modes, effects, and criticality analysis (FMECA).

Brief summary of characteristics

  • A systematic, highly structured assessment relying on evaluation of component failure modes and team experience to generate a comprehensive review and ensure that appropriate safeguards against system performance problems are in place
  • Used as a system-level and component-level risk assessment technique
  • Applicable to any well-defined system
  • Sometimes performed by an individual working with system experts through interviews and field inspections, but also can be performed by an interdisciplinary team with diverse backgrounds and experience participating in group review meetings of system documentation and field inspections
  • A technique that generates qualitative descriptions of potential performance problems (failure modes, causes, effects, and safeguards) as well as lists of recommendations for reducing risks
  • A technique that can provide quantitative failure frequency or consequence estimates

Most common uses

  • Used primarily for reviews of mechanical and electrical systems, such as fire suppression systems and vessel steering and propulsion systems
  • Used frequently as the basis for defining and optimizing planned equipment maintenance because the method systematically focuses directly and individually on equipment failure modes
  • Effective for collecting the information needed to troubleshoot system problems

Limitations of FMEA

Although the FMEA methodology is highly effective in analyzing various system failure modes, this technique has four limitations:

Examination of human error is limited. A traditional FMEA uses potential equipment failures as the basis for the analysis. All of the questions focus on how equipment functional failures can occur. A typical FMEA addresses potential human errors only to the extent that human errors produce equipment failures of interest. Misoperations that do not cause equipment failures are often overlooked in an FMEA.

Focus is on single-event initiators of problems. A traditional FMEA tries to predict the potential effects of specific equipment failures. These equipment failures are generally analyzed one by one, which means that important combinations of equipment failures may be overlooked.

Examination of external influences is limited. A typical FMEA addresses potential external influences (environmental conditions, system contamination, external impacts, etc.) only to the extent that these events produce equipment failures of interest. External influences that directly affect vessel safety, port safety, and crew safety are often overlooked in an FMEA if they do not cause equipment failures.

Results are dependent on the mode of operation. The effects of certain equipment failure modes often vary widely, depending on the mode of system operation. For example, the steering system on a vessel is of little importance while the vessel is docked and is unloading cargo. A single FMEA generally accounts for possible effects of equipment failures only during one mode of operation or a few closely related modes of operation. More than one FMEA may, therefore, be necessary for a system that has multiple modes of operation.

Source: USCG Risk-based Decision-making (RBDM) Guidelines.

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Copyright ©2000-2019 Geigle Safety Group, Inc. All rights reserved. Federal copyright prohibits unauthorized reproduction by any means without permission. Disclaimer: This material is for training purposes only to inform the reader of occupational safety and health best practices and general compliance requirement and is not a substitute for provisions of the OSH Act of 1970 or any governmental regulatory agency. CertiSafety is a division of Geigle Safety Group, Inc., and is not connected or affiliated with the U.S. Department of Labor (DOL), or the Occupational Safety and Health Administration (OSHA).