The P-F Curve (Potential Failure to Functional Failure Curve) is a fundamental conceptual tool in Reliability-Centred Maintenance (RCM) and Condition-Based Maintenance (CBM). It visually represents the progressive deterioration of an asset's condition over time, providing a framework for optimizing proactive maintenance interventions. The P-F curve is the gold standard for rotating equipment and mechanical systems because these assets typically show clear, measurable signs of stress before they seize.  The point P is the time when deterioration is first detectable. F is the point of failure. 

We invite you to explore the interactive diagram below which has been adapted specifically for structural fatigue cracking.