Certified Maintenance & Reliability Professional (CMRP) Practice Exam

How should understanding the P-F curve affect PM frequency?

1. It should be increased beyond the P-F interval

2. It should be equal to the P-F interval

3. It should be less than the P-F interval

4. It has no effect on PM frequency

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

Understanding the P-F curve is crucial in determining the appropriate frequency of preventive maintenance (PM). The P-F curve illustrates the progression of failure in equipment; 'P' represents the point of potential failure, while 'F' illustrates the point of functional failure. Between these two points, there is a window of opportunity for maintenance to be performed before the equipment actually fails and affects operations. By recognizing that the period between the potential failure (P) and functional failure (F) represents a risk, the PM frequency should realistically be set at a rate that is less than the P-F interval. This approach ensures that maintenance activities occur before potential failures become critical, allowing for intervention while the asset is still functioning. In other words, the maintenance activity is proactively scheduled to mitigate the risk of unexpected breakdowns, thus enhancing overall reliability and performance. Those who consider increasing PM frequency beyond the P-F interval may find it unnecessary and may compromise resources and productivity, while aligning maintenance to the P-F interval might not be proactive enough. Not considering the P-F concept at all could lead to insufficient maintenance, resulting in operational inefficiencies or unplanned downtime. Understanding this relationship can lead to a more strategic approach to maintenance scheduling and resource management.