Comparison
Preventive vs predictive maintenance: which assets need which
Preventive maintenance services equipment on a fixed schedule of time or usage, whether it needs it or not. Predictive maintenance measures the condition of the equipment, such as vibration, temperature or current, and schedules work when the data shows a failure developing. Predictive costs more to set up and pays back on critical, expensive or unpredictable assets; preventive remains right for many others.
Understand
Side by side
| Preventive | Predictive | |
|---|---|---|
| Trigger | Calendar or usage (hours, cycles) | Measured condition and trend |
| Data needed | Maintenance plan and history | Sensor data, history of failures, context |
| Setup effort | Low | Higher: sensors, connectivity, models, process |
| Risk | Over maintenance, and failures between intervals | False alarms or missed faults if poorly tuned |
| Best for | Predictable wear, low failure cost, regulated checks | Critical assets, costly or random failures |
How it works
How to choose per asset
- 1Rank criticality. What does a failure cost in lost output, safety and repair?
- 2Check the failure pattern. Age related wear suits preventive; random failures with a detectable warning suit predictive.
- 3Check measurability. Can vibration, temperature, current or oil condition show the fault forming?
- 4Decide and review. Assign a strategy per asset and revisit it with failure data each year.
Condition based maintenance in between
Condition based maintenance acts when a measured value crosses a limit, such as vibration above an alarm level. Predictive maintenance goes further and projects when the limit will be reached, from the trend. Condition based is often the practical first step: simpler to set up, and it builds the data history predictive models need. ISO 17359 gives general guidance on condition monitoring programmes.
Work with us
How we help
We help plants rank assets, instrument the critical ones, connect the data and turn alerts into work orders in their maintenance system. We start with one asset class and expand only when the alerts prove useful to the maintenance team.
What we have built
Our QR based maintenance and video SOP systems support blast furnaces, coke ovens, rolling mills and processing lines, with more than ₹80,000 crore (about US$9.6 billion) of machinery under maintenance.
Figures are company reported from past projects. They are not independently audited benchmarks and are not a promise for another plant. Read the case studies.
Frequently asked questions
Is predictive maintenance always better than preventive?
No. For assets with predictable wear and cheap failures, preventive maintenance is simpler and cheaper. Predictive maintenance is worth it where failures are costly and give a measurable early warning.
What data do you need for predictive maintenance?
Condition data from sensors, such as vibration, temperature and current, at a suitable sampling rate; operating context such as load and product; and a history of failures and repairs to learn from.
Can we do predictive maintenance on old machines?
Yes. Retrofit sensors can be fitted to old machines without changing their controls.
What is reactive maintenance?
Running equipment until it fails and then repairing it. It is acceptable for non critical, cheap items with redundancy, and costly for anything else.
Related reading
References
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Reviewed by Amey Kadle, Founder, Ajinkya Technologies. Last reviewed: .