Run-to-failure is the maintenance policy of intentionally operating an asset until it fails, then repairing or replacing it - it is appropriate only when failure impact is low and replacement is quick and inexpensive.

What Is Run-to-failure?

• Definition: Reactive strategy with no scheduled intervention before functional failure occurs.
• Suitable Assets: Non-critical, low-cost components with minimal safety and production impact.
• Unsuitable Assets: Bottleneck tools or components whose failure causes major downtime or contamination risk.
• Operational Requirement: Fast replacement path and available spare parts when failure happens.

Why Run-to-failure Matters

• Cost Advantage in Niche Cases: Avoids preventive labor and part replacement for low-risk items.
• Planning Risk: Unexpected failure timing can disrupt operations if criticality is misclassified.
• Safety Consideration: Must never be used where failure creates personnel or environmental hazard.
• Throughput Exposure: In fabs, misuse on important subsystems can cause significant output loss.
• Policy Clarity: Explicit RTF designation prevents accidental neglect on high-impact assets.

How It Is Used in Practice

• Criticality Screening: Apply RTF only after formal failure consequence analysis.
• Spare Strategy: Keep low-cost replacement inventory for fast corrective action.
• Periodic Recheck: Re-evaluate policy if asset role or process dependency changes.

Run-to-failure is a selective economic strategy, not a default maintenance mode - it works only when failure consequences are truly constrained and manageable.