What Is Condition-Based Maintenance (CBM)?
Also known as: CBM, condition monitoring, on-condition maintenance
Definition
Condition-based maintenance (CBM) triggers maintenance when a measured indicator of equipment health, such as vibration, temperature or oil contamination, crosses a defined limit, instead of on a fixed calendar or run-hour schedule.
Condition-Based Maintenance (CBM) Explained
CBM rests on a condition indicator and an alert limit. Examples include vibration velocity on a motor, bearing temperature, differential pressure across a filter, or particle count in lubricating oil. Readings are taken by sensors, handheld instruments on an inspection route, or lab samples. When a reading passes the limit, a work order is raised.
In maintenance systems, CBM is usually implemented with measuring points or meters. SAP uses measuring points (created through IK01) and counters with readings that can trigger notifications. IBM Maximo uses meters and condition monitoring points with alert actions. The key setup tasks are defining the points on the asset hierarchy, choosing limits, and deciding who receives the resulting work.
CBM is often confused with predictive maintenance. A useful distinction: CBM reacts when a limit is crossed, while predictive maintenance forecasts the time remaining from the trend. In many plants CBM is the practical first step, because threshold rules are easy to explain and audit, and it requires less failure history than a trained model.
CBM works only when a failure develops gradually and can be detected early enough to act. Sudden failures, such as an electrical short or a casting crack under shock load, are not helped by it.
Why It Matters
- Avoids replacing parts that still have life, which time-based PM often does.
- Catches developing faults between PM intervals, reducing surprise failures.
- Needs far less data science than predictive models, so it can be started with existing instruments and inspection routes.
- Creates the measured history that later supports predictive models.
In Practice
A hydraulic press has a filter replaced every 3 months under PM. With CBM, a pressure differential reading is taken on each shift round. The filter is changed when differential pressure crosses the manufacturer's limit. Some months it is changed at 6 weeks because of dirty fluid, and some months it runs 5 months. Each reading is stored as a meter reading against the asset, so the interval can be reviewed against actual data.
Frequently Asked Questions
Is condition-based maintenance the same as predictive maintenance?
They overlap but differ. CBM acts when a reading crosses a limit. Predictive maintenance forecasts time to failure from trends or models. Many programs start with CBM and evolve toward prediction.
What equipment suits CBM?
Equipment with failure modes that develop gradually and show up in measurable signals, such as rotating machinery, hydraulic systems, filters, and electrical connections with thermal signatures.
How does CBM connect to ERP or CMMS?
Readings are stored as meter or measuring point values against the asset. When a limit is crossed the system raises a notification or work order, with parts and labor planned in the normal way.
Related Terms
Predictive Maintenance (PdM)
Predictive maintenance (PdM) uses sensor readings, operating data and failure history to estimate when equipment is likely to fail, so repairs are scheduled shortly before that point rather than on a fixed calendar or after a breakdown.
Preventive Maintenance (PM)
Preventive maintenance (PM) is planned servicing of equipment at set time or usage intervals, such as lubrication, inspection or part replacement, performed before a failure occurs to reduce unplanned downtime and extend asset life.
CMMS (Computerized Maintenance Management System)
A CMMS (Computerized Maintenance Management System) is software that records equipment, schedules preventive maintenance, issues and tracks maintenance work orders, and manages spare parts, so a maintenance team can plan work and keep a history of every repair.
Reliability-Centered Maintenance (RCM)
Reliability-centered maintenance (RCM) is a structured analysis that determines, for each asset function and failure mode, the most effective maintenance strategy, such as preventive, condition-based, redesign or run-to-failure, based on consequence and failure behavior.
SPC (Statistical Process Control)
SPC (Statistical Process Control) is the use of control charts and statistical rules to monitor a process in real time, distinguishing normal common-cause variation from special-cause variation that signals a genuine change requiring action.
Go Deeper
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