CPM Maintenance and Reliability 3 — Questions and Answers
Question 1: The 'P-F interval' in predictive maintenance refers to:
- The period between planned and forced outages
- The time between a potential failure signal and functional failure (Correct answer)
- The preventive maintenance frequency for critical assets
- The performance factor used in OEE calculation
Correct answer: The time between a potential failure signal and functional failure
The P-F interval is the time between the point where a potential failure becomes detectable (P) and when it becomes a functional failure (F), defining the window for intervention.
Question 2: Which maintenance key performance indicator (KPI) directly measures the percentage of total maintenance time spent on unplanned repairs?
- Maintenance cost as % of replacement asset value
- Reactive maintenance ratio (Correct answer)
- Schedule compliance rate
- Planned maintenance percentage (PMP)
Correct answer: Reactive maintenance ratio
The reactive maintenance ratio tracks the proportion of maintenance hours spent on unplanned, emergency repairs versus total maintenance hours.
Question 3: In a Failure Mode and Effects Analysis (FMEA), the Risk Priority Number (RPN) is calculated as:
- Severity × Occurrence × Detection (Correct answer)
- Probability × Consequence × Exposure
- Frequency × Severity × Detectability
- Likelihood × Impact × Vulnerability
Correct answer: Severity × Occurrence × Detection
RPN = Severity × Occurrence × Detection, where each factor is rated on a scale (typically 1–10) to prioritize failure modes for corrective action.
Question 4: A plant uses thermographic infrared scanning during operation to detect hot spots in electrical panels. This is an example of:
- Condition-based monitoring (Correct answer)
- Run-to-failure strategy
- Periodic overhaul maintenance
- Corrective maintenance
Correct answer: Condition-based monitoring
Infrared thermography is a condition monitoring technique that detects thermal anomalies indicating developing faults without requiring equipment shutdown.
Question 5: Which term describes the probability that a system will perform its required function for a specified period under stated conditions?
- Availability
- Maintainability
- Reliability (Correct answer)
- Durability
Correct answer: Reliability
Reliability is specifically defined as the probability of a system performing its intended function without failure over a given time under defined conditions.
Question 6: A plant's computerized maintenance management system (CMMS) is BEST used to:
- Automatically perform predictive data analysis on equipment sensors
- Track work orders, asset history, and spare parts inventory (Correct answer)
- Replace the need for skilled maintenance technicians
- Design preventive maintenance procedures from scratch
Correct answer: Track work orders, asset history, and spare parts inventory
A CMMS is fundamentally a database and workflow tool that manages work orders, asset records, maintenance history, and inventory rather than replacing engineering judgment.
Question 7: When performing a criticality analysis, assets are ranked based on:
- Age and purchase price only
- Consequence of failure and probability of failure (Correct answer)
- Number of spare parts available
- Time required to perform preventive maintenance
Correct answer: Consequence of failure and probability of failure
Criticality analysis ranks assets by combining the consequence of failure (safety, production, cost impact) with the likelihood of failure to prioritize maintenance resources.
CPM Maintenance and Reliability 3
The 'P-F interval' in predictive maintenance refers to: