Lesson 8: Failure analysis procedures to support sustainable maintenance

In this lesson, we’ll explore failure analysis procedures aimed at preventing failures and ensuring sustainable maintenance practices. Failure analysis is a critical process in identifying root causes and mitigating future issues.


  • Failure analysis is a systematic approach to understanding failures, their costs, consequences, and most importantly, their root causes.
  • A thorough failure analysis involves various disciplines, and prioritizing which failures to analyze can be done using Pareto analysis.

Pareto Analysis: Prioritizing Failures

  • Pareto analysis is based on the 80/20 rule, which suggests that 80% of problems stem from 20% of root causes.
  • Applying this principle to maintenance, it implies that a minority of components (20%) may be responsible for the majority (80%) of breakdowns.
  • Prioritizing and addressing these critical components first can yield significant improvements in maintenance efficiency.

FMEA: Quantifiable Failure Analysis

  • Failure Mode and Effects Analysis (FMEA) is a robust failure analysis method that provides quantifiable results.
  • FMEA is commonly used in product and process design to reduce the likelihood of failures.
  • It’s particularly useful when evaluating the impact of material, component, and equipment failures on the higher functional levels of a system.
  • In product FMEA, the focus is on eliminating expected failures early in the design phase, including issues related to material selection, geometry, and dimensional specifications.
  • Risk priority numbers (RPNs) are assigned to failure modes, representing the product of severity, likelihood, and detectability scores. An RPN exceeding 100 often necessitates risk reduction measures before mass production.
  • Process FMEA aims to reduce the potential risk associated with the manufacturing process, addressing issues like improper assembly or high process variability.
  • Teams of experts with diverse experience in design, manufacturing, maintenance, and quality should conduct FMEA.
  • A well-established list of defect types helps identify potential issues.


  • Failure analysis procedures are essential for sustainable maintenance.
  • Pareto analysis helps identify critical failures for prioritized attention.
  • FMEA provides quantifiable results and is used in both product and process design.
  • Reducing the number of potential failures through these methods can lead to more sustainable maintenance practices.
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