Failure Modes and Effects Analysis (FMEA) an analytical tool that is used in Risk Management to identify various ways in which systems elements can fail and what’s their overall impact (consequence) to other elements and/or the overall system.  The results are processed thru Failure Modes Effects and Criticality Analysis (FMECA) in which each potential failure is classified/prioritize according to the combined influence of its severity and its probability of occurrence. These results can be achieved either quantitatively or qualitatively. The quantitative process uses existing failure data, while the qualitative approach uses a subjective ranking procedure conducted by a team of people with an understanding of the system under review.  A FMEA should be initiated as soon as preliminary design information is available. [1]

Definition: Failure Modes and Effects Analysis (FMEA) is a tool used for identifying all possible failures in a design, a manufacturing process in a product.

Purpose of Failure Modes and Effects Analysis (FMEA)

The purpose of the FMEA is to prevent, reduce or eliminate potential product failures by starting with the top risks with the greatest consequences.

The use of FMEA and FMECA [1]

• Development of system requirements that minimize the likelihood of failures
• Development of methods to design and test systems to ensure that the failures have been eliminated.
• Evaluation of the requirements of the customer to ensure that those do not give rise to potential failures.
• Identification of certain design characteristics that contribute to failures, and minimize or eliminate those effects.
• Tracking and managing potential risks in the design. This helps avoid the same failures in future projects
• Highlight single-point failures requiring corrective action
• Aid in developing test methods and troubleshooting techniques
• Provide a foundation for qualitative reliability, maintainability, safety, and logistics analyses
• Provide estimates of system-critical failure rates
• Provide a quantitative ranking of the system and/or subsystem failure modes relative to mission importance
• Identify parts and systems most likely to fail
• Minimize overall costs by identifying single-point failures and other areas of concern prior to manufacturing
• Provide a baseline for troubleshooting that can be used for identifying corrective actions for a given failure
• Results can be used to perform a variety of other analyses, such as Fault Tree Analysis (FTA), or/and Reliability Centered Maintenance Analysis (RCMA)

Failure Modes and Effects Analysis (FMEA) Provides Insight Into

• Functional analysis of highly complex systems
• Observation of combined effects of simultaneous, non-critical events on the highest level event
• Evaluation of system reliability
• Identification of potential design defects and safety hazards
• Evaluation of corrective actions
• Evaluate compliance with the (input) system safety/reliability requirements Identification and simplification of maintenance requirements and troubleshooting procedures
• Elimination of causes for observed failures

Difference Between Fault Tree Analysis (FTA) and Failure Mode Effects and Criticality Analysis (FMECA)

Fault Tree Analysis (FTA) is a “top-down” method of analysis compared to Failure Modes Effects and Criticality Analysis (FMECA) which is a “bottoms up” method. FMECAs and FTAs are compatible methods of risk analysis, with the choice of method depend on the nature of the risk to be evaluated. There are some differences. Because FTA is a top-down analysis there is a higher probability of misinterpretation at the lowest level. On the other hand, with the FMECA starting at the lowest level, it will probably result in a better method of risk analysis (assuming the lowest level data is available). Also, the FMECA considers only single failures while FTA considers multiple failures which will impact accuracy.

 See Damage Mode & Effects Analysis (DMEA)

AcqTips:

• The single biggest failure people make with FMEAs is to spend time completing the document and then storing it in a filing cabinet. The FMEA is the ultimate dynamic document, meaning that it should survive as long as the process or product with which it is associated.

AcqLinks and References:

• [1] Website: ACQuipedia – Failure Modes and Effects Analysis

Updated: 7/25/2021

Rank: G30