The P-F Curve marks two, important points: the potential failure point and the functional failure point.
Potential Failure: The “P” in P-F Curve refers to the potential failure point. This is the point where failure signs can first be detected.
Functional Failure: The “F” in the curve marks the functional failure of an asset. The functional failure is the point where an asset or piece of equipment actually fails.
The “P” and “F” point in the curve mark the P-F Interval: the time between when a failure can first be detected and when it is actually affecting operations.