Criticality Analysis
Criticality Analysis (CA) is a systematic methodology that evaluates how asset failures impact organizational performance (safety, production, cost, environment) to rank plant assets for selecting reliability strategies, prioritizing work, developing preventive/predictive maintenance (PM/PdM), and optimizing material classification.
In shop floor maintenance, teams assign a Criticality Rating (composite score) to each asset by scoring failure likelihood, severity of consequences, and detectability, then normalizing against total weighted points. Results drive work prioritization in the CMMS (e.g., ServiceGrid), ensuring high-criticality assets receive PdM/condition monitoring while low-criticality assets use run-to-failure or PM. CA also informs spare parts inventory levels (high-criticality = higher stock) and capital improvement planning. The process is iterative, with assets re-evaluated annually to align with evolving business objectives.
- Subjective 'Gut-Feel' Ranking: Assigning criticality based on personal bias rather than data-driven criteria (e.g., ignoring historical failure rates or safety data), leading to misallocated resources.
- Static Analysis: Conducting CA once and never updating it, causing criticality scores to become obsolete as production processes or asset roles change.
- Over-Criticalizing Assets: Labeling too many assets as 'Critical' (e.g., >30% of fleet), which dilutes the prioritization value and prevents effective resource focus on truly high-risk equipment.
How does CA differ from FMEA?
FMEA is a bottom-up, failure-mode-specific analysis identifying how a component fails; CA is a top-down assessment of how much the failure impacts the mission, ranking assets by consequence severity.
What is the formula for Quantitative Mode Criticality?
Mode Criticality = Item Unreliability × Mode Ratio of Unreliability × Probability of Loss (Severity).
Can CA be purely qualitative?
Yes; qualitative CA uses a Criticality Matrix plotting Severity (horizontal) vs. Likelihood of Occurrence (vertical) to rank failure modes without numerical calculations.
What criteria are used for scoring in CMMS (e.g., ServiceGrid)?
Standard criteria include Safety Impact, Production Loss, Maintenance Cost, Environmental Risk, and Detectability (lead time before failure).
How is CA integrated with Reliability-Centered Maintenance (RCM)?
CA ranks assets; RCM then selects the optimal maintenance strategy (e.g., PdM, PM, redesign) only for high-criticality assets identified by CA.