Certified Maintenance & Reliability Professional (CMRP) Practice Exam

What should the relationship between preventive maintenance (PM) frequency and the P-F interval be?

1. PM should be greater than the P-F interval

2. PM should be less than the P-F interval

3. PM and P-F frequency should be equal

4. PM frequency is not related to P-F interval

The correct answer is: PM should be less than the P-F interval

The correct answer reflects a crucial principle in maintenance strategy, which is that the frequency of preventive maintenance (PM) should be less than the potential failure (P-F) interval. The P-F interval represents the time between the point when a potential failure can be detected and the actual failure occurs. By scheduling preventive maintenance at intervals shorter than this P-F duration, organizations can effectively mitigate the risk of unplanned downtime. This ensures early detection and intervention before a failure can lead to equipment breakdowns, which may result in costly repairs or operational disruptions. If PM were to occur at intervals greater than the P-F interval, there is a risk that a failure might occur before the next maintenance task is performed, leading to unexpected equipment failure. In contrast, if PM were to equal the P-F interval, it may provide the bare minimum of protection, but it is generally more prudent to have a buffer to account for variances and uncertainties in equipment performance and failure modes. Thus, having PM performed more frequently than the P-F interval is a proactive approach to enhance reliability and maintain operational continuity.