What is the difference between preventive maintenance and predictive maintenance?

• A. Preventive uses calendar-based intervals; predictive uses condition data to trigger maintenance just-in-time.
• B. Preventive is based on condition data; predictive is calendar-based.
• C. Preventive is only for safety-critical equipment; predictive is for non-critical.
• D. Preventive delays maintenance until a failure occurs; predictive schedules maintenance ahead of time.

Answer: (A)

It’s about how maintenance gets triggered: preventive maintenance follows a set calendar or usage schedule, while predictive maintenance uses condition data to decide when to act.

Preventive maintenance is planned in advance based on time or usage, following manufacturer recommendations or internal schedules. It aims to prevent failures by performing work at regular intervals, regardless of the actual condition of the equipment. Predictive maintenance relies on data from sensors and tests (like vibration, temperature, oil analysis, wear debris) and analyzes trends to predict when a component will likely fail, so maintenance can occur just before that point. This reduces downtime and unnecessary work compared to fixed intervals.

The other statements mix up what triggers maintenance: preventive isn’t based on real-time condition data, and predictive isn’t simply calendar-based. Also, preventive isn’t about delaying maintenance until a failure occurs; it’s proactively scheduled.