15 Condition-Based Monitoring Techniques (2025)
Condition-based monitoring (CBM) is a predictive maintenance approach that relies on real-time data to assess the health of machinery and systems. By monitoring parameters such as vibration, temperature, oil condition, and electrical signals, CBM enables proactive maintenance before failures occur.
It is widely adopted in industries like manufacturing, oil and gas, power generation, aerospace, and marine operations to improve reliability, reduce downtime, and optimise maintenance efficiency.
Condition Monitoring Techniques
1. Vibration Monitoring
Vibration monitoring is used to detect faults in rotating machinery by analysing vibration frequency, amplitude, and waveform patterns. Every mechanical component exhibits unique vibration signatures during normal operation. When components like bearings, shafts, or gears become misaligned, unbalanced, or worn out, the vibration patterns change.
Techniques like Fast Fourier Transform (FFT), shock pulse analysis, and time waveform analysis convert time-domain signals into frequency-domain data, making it easier to pinpoint issues. Vibration sensors are placed on critical locations, such as bearing housings or motor shafts, to provide early warnings of mechanical failures. This technique is crucial for predictive maintenance in pumps, compressors, turbines, and electric motors.
2. Oil Analysis
Oil analysis evaluates the condition of lubricants to identify contamination, oxidation, wear particles, and additive depletion. Oil collects microscopic debris from moving parts, and these particles provide clues about internal component wear. Common parameters tested include viscosity, total acid number (TAN), water content, and levels of metals like iron or copper.
Techniques such as spectrographic analysis, ferrography, and infrared spectroscopy detect the presence of contaminants and breakdown by-products. Wear debris analysis (WDA) allows maintenance teams to trace specific failure modes by examining particles in oil samples. Combined with real-time sensors, oil analysis plays a vital role in hydraulic systems, engines, and gearboxes.
3. Thermography
Thermographic testing uses infrared cameras to measure surface temperature across equipment. It detects heat anomalies caused by friction, insulation failure, electrical overload, or fluid leakage. Infrared thermography translates heat emissions into visual images called thermograms, highlighting hot and cold spots. These thermal patterns often reveal hidden issues that are not visible to the naked eye.
Thermography is non-contact and can be performed while machinery is running, making it ideal for inspecting motors, bearings, transformers, steam lines, and HVAC systems. It improves safety by identifying overheating components early, preventing fire hazards and mechanical breakdowns.
4. Ultrasonic Monitoring
Ultrasonic monitoring utilises sound frequencies above the human hearing range (above 20 kHz) to detect abnormalities in machinery. It is used for leak detection and internal flaw detection. For leak detection, ultrasound sensors pick up the high-frequency noise produced by escaping compressed air, gas, or steam. In flaw detection, sound waves are transmitted into solid materials; the reflected waves reveal inconsistencies like cracks, delaminations, or voids. Techniques such as airborne and structure-borne ultrasound help detect early signs of bearing failure or lubrication issues. Ultrasonic testing is also used for steam trap diagnostics and electrical discharge detection.
5. Motor Monitoring
Motor monitoring refers to a suite of techniques aimed at identifying electrical or mechanical problems in electric motors. Motor Circuit Analysis (MCA) is an offline method where an AC signal is introduced to test motor windings for resistance, impedance, and insulation integrity. Motor Current Signature Analysis (MCSA) is an online method that detects faults in the rotor, stator, or power supply by analysing variations in the current waveform.
These techniques are supplemented by temperature sensors, vibration sensors, and power consumption meters to provide a comprehensive view of motor health. This is critical for early detection of winding shorts, power imbalances, or rotor bar defects.
6. Electrical Monitoring
Electrical monitoring involves real-time assessment of voltage, current, resistance, power factor, and insulation quality in electrical systems. Techniques such as megohmmeter testing measure insulation resistance, while dielectric withstand (hipot) testing evaluates a system's ability to handle high voltages without breaking down.
Surge and impedance tests are used to detect internal cable faults and degraded components. Power signature analysis examines the relationship between voltage and current to identify inefficient energy usage. This technique ensures safety, reduces fire risks, and increases the reliability of power distribution equipment, control panels, transformers, and battery banks.
7. Acoustic Emission
Acoustic emission monitoring detects high-frequency waves generated by the rapid release of energy from materials under stress. These stress waves occur when microcracks form or propagate, and are captured by piezoelectric sensors. This method is especially effective in high-pressure vessels, tanks, and structural components. It enables early detection of fatigue, corrosion, and crack formation without disassembling the equipment. Acoustic emission analysis is valuable for critical applications in aerospace, civil engineering, and nuclear power facilities.
8. Electromagnetic Measurement
Electromagnetic measurement techniques detect flaws using variations in magnetic fields. Eddy current testing is widely used to inspect conductive materials for surface and subsurface cracks, corrosion, or wall thinning. Magnetic particle inspection involves applying magnetic particles to a magnetised component; the particles gather at areas with flux leakage, indicating defects. Magnetic flux leakage and pulsed eddy current testing are applied in pipelines, tanks, and heat exchangers. These methods are non-invasive and suitable for materials like stainless steel, aluminium, and copper alloys.
9. Laser Interferometry
Laser interferometry detects displacement, strain, and vibration by measuring changes in interference patterns of coherent laser beams. It is highly sensitive to microscopic surface defects and subsurface anomalies. Techniques like electronic speckle pattern interferometry (ESPI), laser shearography, and digital holography are used in aerospace, precision engineering, and semiconductor manufacturing. These methods reveal stress points and deformations in high-performance materials before visible damage appears, making them ideal for high-precision monitoring applications.
10. Radiography
Radiographic testing involves using X-rays or neutron radiation to capture internal images of materials and components. It reveals hidden flaws such as cracks, voids, porosity, and welding defects. Radiography is non-destructive and applicable to both metallic and non-metallic components. With the help of digital detectors, radiographic images can be analysed for early-stage corrosion or fatigue damage. Industries such as oil and gas, power generation, and aerospace use this method to inspect pressure vessels, pipelines, castings, and welded structures.
11. Performance Monitoring
Performance monitoring compares real-time operational data against baseline values or engineered specifications to assess equipment health. Parameters like flow rate, speed, pressure, and energy consumption are continuously tracked. Deviations from expected performance indicate potential issues like blockages, wear, misalignment, or fluid leakage. This method is often used for boilers, turbines, heat exchangers, and pumps to detect efficiency losses and optimise output. Performance monitoring supports energy-saving initiatives and helps schedule maintenance based on data-driven thresholds.
12. Temperature Monitoring
Temperature monitoring tracks the heat generated by equipment components to detect anomalies in operation. Sudden increases in temperature may indicate bearing failure, insulation breakdown, or lubrication issues. Sensors like thermocouples, resistance temperature detectors (RTDs), and infrared devices provide real-time data for early detection. Consistent tracking of hotspots in electrical panels, motors, and hydraulic systems prevents overheating and catastrophic failures.
13. Pressure Monitoring
Pressure monitoring is critical in systems that rely on maintaining specific fluid or gas pressures. Sensors detect abnormal fluctuations that may result from leaks, blockages, or pump failures. Real-time alerts help prevent equipment damage, process deviations, and safety hazards. Pressure monitoring is widely used in chemical processing, HVAC systems, hydraulic machinery, and pneumatic tools.
14. Humidity Monitoring
Humidity monitoring measures the level of moisture in the air to prevent corrosion, microbial growth, and product spoilage. High humidity accelerates oxidation in metal surfaces and impacts the stability of sensitive materials like pharmaceuticals and food. Hygrometers and humidity sensors are used in controlled environments such as cleanrooms, storage areas, and processing plants. This technique supports quality control and environmental compliance.
15. Visual Inspection (Quantified)
Quantified visual inspection transforms traditional visual checks into measurable data collection. Inspectors use standardised checklists, calibrated tools, and documentation to assess visible defects such as wear, corrosion, and fluid leakage. Images and measurements are recorded for comparison over time, allowing trend analysis and predictive planning. When results are consistently measured and logged, visual inspection becomes a legitimate condition monitoring tool used in structural maintenance, pipelines, and mechanical equipment.
Conclusion
Condition-based monitoring has become a cornerstone of modern predictive maintenance strategies. By continuously analysing the health of critical assets, businesses can proactively address faults before they escalate, leading to enhanced operational efficiency, safety, and cost savings.
If you're looking to implement or optimise condition-based monitoring solutions in your facility, especially within the Malaysian industrial landscape, now is the time to explore trusted experts in the field—such as Inframatrix, a leading provider of integrated CBM solutions.
Frequently Asked Questions (FAQ)
What is condition-based monitoring (CBM)?
Condition-based monitoring (CBM) is a maintenance strategy that uses real-time data from sensors to assess equipment condition and detect signs of wear or failure. It replaces traditional scheduled maintenance with a predictive approach, allowing interventions only when necessary. CBM is widely used in industries like manufacturing, oil and gas, power generation, aerospace, and marine operations.
Why is condition-based monitoring important?
Condition-based monitoring is important because it helps detect early signs of equipment failure before a breakdown occurs. By identifying anomalies in parameters like vibration, temperature, or pressure, businesses can avoid costly repairs, unplanned downtime, and safety incidents. It plays a vital role in ensuring the reliability of critical assets.
What are the benefits of condition-based monitoring?
The main benefits of condition-based monitoring include reduced unplanned downtime, lower maintenance costs, extended equipment lifespan, improved safety, and optimised asset performance. By focusing maintenance efforts only when needed, CBM prevents unnecessary interventions and contributes to more efficient and cost-effective operations.
How is condition-based monitoring different from condition-based maintenance?
Condition-based monitoring (CBM) is the process of collecting data from sensors to understand equipment health. Condition-based maintenance uses that data to schedule and perform necessary maintenance. In short, CBM gathers insights, while condition-based maintenance acts on them. CBM is a tool, while CBM programs define how that data is used in real-world operations.