Infrared thermography converts thermal radiation into a representation of apparent temperature distribution when collection preserves context, parameters, and comparability. In industrial maintenance, a standalone color image has limited decision value. Load, emissivity, reflected apparent temperature, distance, angle, environmental condition, observed material, and instrument configuration need to accompany the evidence.
Operational value emerges when a route answers a question tied to a failure mode, produces a consistent classification, opens the appropriate output in SAP PM, and returns to the same point after intervention. Qualified professionals use the technique to support decisions. Safety procedures, risk assessment, confirmation by another method, and engineering judgment remain necessary.
Define the condition the route must detect
A route starts with function and the mechanism of interest. In an electrical panel, the question may involve thermal asymmetry, localized heating, or abnormal development under comparable load. Bearings, refractory linings, heated pipes, and steam systems require different questions, surfaces, and interference controls. A camera records infrared energy and converts it into apparent temperature. The displayed value depends on instrument inputs and scene conditions.
ISO 18434-1 provides general procedures for thermography applied to condition monitoring and diagnostics, including terminology, data collection, interpretation, emissivity, reflection, and attenuating media. The licensed edition should guide the company procedure. Alarm criteria, personnel qualification, and safety rules still depend on the asset, installation, manufacturer guidance, and local governance.
Four conditions for a defensible comparison
- Equivalent operating function: compare components under similar load, regime, and environment.
- Documented parameters: record adopted emissivity, reflected apparent temperature, distance, range, focus, and relevant atmospheric condition.
- Controlled geometry: preserve point, angle, framing, and reference surface to reduce measurement variation.
- Predefined response: determine when to repeat, confirm, notify, plan, or escalate an anomaly.
Comparing a loaded connection with an out-of-service one produces a misleading contrast. Surfaces with different emissivities can yield incompatible numbers. A window transparent to the human eye may be opaque in the infrared band. Dust, oil, paint, reflection from a hot source, wind, and distance can also alter the reading. Data quality begins before image capture.
Qualitative assessment, quantitative assessment, and trending
A qualitative approach looks for patterns and differences, such as a relative hot spot, an unexpected distribution, or asymmetry between comparable components. A quantitative approach requires tighter control of inputs to estimate apparent temperature with known uncertainty. Trending follows the same point under reproducible conditions. All three can support a program, but the maintenance record should identify which approach supported the decision.
A thermal delta also needs an explicit reference. It may represent the difference among comparable phases, between a component and ambient conditions, between a point and its surrounding area, or between equivalent campaigns. Each reference answers a different question. Mixing references in one time series breaks the trend. Applying a universal severity table without verifying applicability creates false precision.
Build the route before sending it to the field
- Associate every point with equipment, functional location, function, and relevant failure mode.
- Define minimum load and stabilization requirements before collection.
- Register the safe position, target, comparable reference, and required parameters.
- Specify mandatory evidence, such as thermal image, visual image, load, and field observation.
- Set immediate repetition rules and confirmation requirements for qualified personnel.
- Connect each result class to a notification, planned order, complementary inspection, or justified closure.
- Define the post-maintenance verification window under similar operating conditions.
For energized electrical equipment, access, approach distance, and enclosure opening follow approved plant procedures and electrical safety requirements. Collection is performed only by authorized personnel within permitted conditions. The desire to obtain an image never justifies removing a barrier, violating an approach boundary, or changing load without operational authorization.
Completed teaching case: panel QD-07
All values in this case are instructional. They do not represent a customer, a benchmark, or PM Run performance. Panel QD-07 supplies three motors on a packaging line. The quarterly route covers incoming and outgoing connections, busbars accessible under the approved procedure, and comparable components at steady state. The selected point was intended to identify localized heating associated with increased resistance at a bolted connection.
Assumptions and collection condition
| Field | Case record |
|---|---|
| Date and time | August 14, 2026, 10:20 |
| Responsible person | Inspector qualified under the internal procedure |
| Circuit load | 76% of rated current, stable for 35 minutes |
| Nearby environment | 29 °C, no direct airflow |
| Surface | Equivalent connections with the same finish and geometry |
| Adopted emissivity | 0.95 on an approved high-emissivity marker |
| Reflected temperature | 31 °C, estimated with the method defined in the procedure |
| Distance and angle | 1.2 m and approximately 20° from normal |
| Reference | Phases A, B, and C under comparable load |
The marker had been included in the plant program and applied while the equipment was not energized. No tape or coating was improvised during inspection. A visual image confirmed identification and framing. Thermal focus was checked before recording the sequence.
Observed data and repeatability check
| Point | Apparent temperature | Comparison |
|---|---|---|
| Phase A connection | 53 °C | Comparable reference |
| Phase B connection | 54 °C | Comparable reference |
| Phase C connection | 82 °C | 28 °C above phase B |
| Repeat after 10 minutes | 81 °C at phase C | Persistent pattern, load between 75% and 77% |
The inspection team did not convert 82 °C directly into a diagnosis. The evidence supported a persistent asymmetry among equivalent components. The inspector verified load, focus, apparent reflections, and stability. The electrical authority reviewed history, confirmed that the previous route had not shown the pattern, and classified the condition using the internal consequence, likelihood, and urgency matrix.
Technical decision and boundaries
The plant opened a high-priority notification and scheduled a physical inspection for the first authorized window, with an internal maximum of 48 hours. The line continued operating because the electrical authority approved the temporary condition based on the local risk matrix and installed protection. This outcome belongs to the teaching case. Another installation could require load reduction or immediate shutdown.
The initial hypothesis was increased resistance at the phase C connection. It guided the work scope without being recorded as a confirmed cause. The plan required de-energization, isolation, verification of absence of voltage, connection inspection, conductor and component assessment, repair to the approved specification, and testing before release.
Notification and work order output in SAP PM
The notification included equipment, functional location, date, detection method, an objective description of the pattern, load condition, apparent temperatures, parameters, internal class, and permitted attachments. Observation was separated from hypothesis. The repeat measurement and the responsible authority's decision remained in the history.
The linked order included preparation, isolation, inspection, correction, and testing operations. Materials were reserved only after compatibility had been verified. A control point required recording the as-found condition, replaced or tightened component, applied criterion, and test result. Planning coordinated the window, electrician, operations, and safety without turning the thermal image into an automatic prescription.
As-found condition and intervention
During the authorized window, the de-energized inspection found heat marks and loss of contact pressure at the phase C connection. The component and termination were replaced according to the installation specification. Adjacent surfaces were evaluated and showed no damage requiring an expanded scope. Electrical testing and assembly inspection met internal criteria before energization.
Order completion captured the as-found condition, completed intervention, materials, time confirmations, and release authority. The cause catalog was completed only after confirmation. The pre-maintenance thermal image remained linked to the notification, while the post-maintenance result entered the follow-up measurement.
Post-maintenance verification
The first verification occurred 24 hours later at 74% to 77% load, 28 °C ambient temperature, and equivalent geometry. Apparent temperatures were 52 °C, 53 °C, and 54 °C on phases A, B, and C. The maximum difference fell to 2 °C. A second reading after 30 days and the next two quarterly routes formed the monitoring window.
The case indicator included more than delta reduction. The team tracked point recurrence, percentage of routes with complete load and parameters, time from detection to notification, time from decision to intervention, and share of orders with a comparable follow-up. The instructional target required 95% complete records and no recurrence across three equivalent checks.
Establish severity without false precision
An internal matrix can combine relative magnitude, trend, functional consequence, redundancy, protection, criticality, and available response time. Absolute temperature can contribute when applicable material, manufacturer, and procedure limits exist. The classification should preserve the evidence and identify the authority that made the decision.
Classes such as observe, schedule, act urgently, or shut down require approved criteria and worked examples. A camera or capture application does not own priority. Thermography alone also cannot identify material composition, internal integrity, or root cause. Visual, electrical, mechanical, or process confirmation may be required.
Indicators for route governance
- Context coverage: collected points with complete load, parameters, and reference.
- Comparability: follow-up readings within the defined operating range.
- Conversion: anomalies that generated the prescribed output within the time rule.
- Closeout quality: orders with as-found condition, action, and test recorded.
- Recurrence: points returning to the same condition class after intervention.
- Effectiveness: confirmed anomalies compared with notifications opened, including analysis of false positives.
A high anomaly rate may indicate real degradation, an overly broad rule, or inconsistent collection. A low rate may reflect stable condition or an insensitive route. Coverage, criticality, and confirmation give the rate meaning. Image volume by itself measures activity.
Connection with the P-F interval and predictive maintenance
The P-F concept helps teams reason about the time between potential failure detection and functional failure. Route frequency should fit within the useful interval while leaving enough time for confirmation, planning, materials, and execution. When the interval is unknown, the uncertainty should be declared and frequency adjusted as evidence accumulates.
Thermography can be one technique within predictive maintenance or condition monitoring. A mature program connects the failure mode, detection capability, decision, completed work, and verification. The broader reliability context is covered in reliability engineering in maintenance.
PM Run's role over SAP PM
PM Run supports planning, mobility, and execution connected to SAP PM. A configured route can reach the field, receive confirmations, and return permitted evidence according to the company's design. Maintenance planning coordinates capacity, scheduling, and feedback. SAP remains the system of record and governance.
PM Run does not provide an infrared camera, sensor, thermography report, diagnosis, predictive algorithm, or ready-made condition dashboard. Technique, limits, qualification, and technical decisions belong to the responsible organization and professionals. To review the operational connection, see PM Run's execution layer for SAP PM.
Limits that belong in the procedure
- Apparent temperature depends on emissivity, reflection, transmission, and geometry.
- A two-dimensional image can hide gradients, internal surfaces, and components outside the field of view.
- Different loads prevent direct comparison unless an appropriate model exists.
- Enclosures, windows, contamination, and atmosphere can attenuate or reflect radiation.
- No thermal contrast does not prove the absence of a defect.
- A confirmed anomaly does not automatically establish root cause.
- Electrical and process safety takes precedence over the collection objective.
Technical references
- ISO 18434-1, Condition monitoring and diagnostics of machines, Thermography, official page accessed August 23, 2026.
- Pacific Northwest National Laboratory, Operations and Maintenance Best Practices Guide, neutral operations and maintenance reference accessed August 23, 2026.
- SAP Help Portal, Process Maintenance Notification, accessed August 23, 2026.
Frequently asked questions
Does a hotter point always require shutdown?
The decision depends on condition, comparability, consequence, and approved installation rules. Repetition and contextual confirmation may be appropriate when the condition can safely remain in service during that assessment. The QD-07 response is not a universal rule.
Can images from different cameras be compared?
Comparison requires traceability for calibration, spectral range, resolution, settings, optics, geometry, and procedure. A trend that changes instruments without controlling these factors should record a series break.
What should return to maintenance history?
Collection condition, observation, classification, decision, completed work, as-found condition, and subsequent verification. This sequence shows whether the technique detected an actionable condition and whether the intervention addressed the observed mechanism.
Thermography routes become more consistent when they form part of an industrial equipment inspection process with a method, criteria, and a defined destination for every anomaly.
