P-F interval inspection frequency

How often to inspect so you catch a failure before it happens.

Calculating…

How it's calculated

Inspection interval = P-F interval ÷ 2 (or ÷ 3) Worst-case warning = P-F − inspection interval

The P-F interval is the time between the point a developing failure can first be detected (P) and functional failure (F). Techniques detect at different points: vibration analysis catches bearing wear months ahead, temperature weeks, noise days and heat or smoke only hours ahead.