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newSchoolWorks.com › VoTechWorks › Manufacturing & Marine › Industrial Maintenance › Externship / Worksite Placement – Industrial Maintenance (Manufacturing & Marine) › Lesson 3
MFG-INDU16-09 · Lesson 3 · 64 clock hours · field

Predictive and Condition-Based Monitoring Field Application

Objective. The student will collect, record, and interpret at least two types of condition-monitoring data (vibration, temperature, ultrasound, or oil/fluid condition) on assigned equipment and submit a written field report communicating findings and recommended actions to the supervising technician.

⚠ Pending professional review

This lesson, its worked examples and its practice questions has not yet been verified by a licensed engineer or certified journey-level tradesperson or by a certification or approval body. It is a study draft and may contain errors. Do not use it as instructions for work on a job site or on live equipment. Always follow your instructor, your supervising professional, and current official references and regulations.

VoTechWorks program approval and accreditation are still in progress. Credentials are issued only by the certifying bodies named in each program, after their own exams.

Predictive and Condition-Based Monitoring: Field Application

Predictive maintenance (PdM) keeps machines running by catching problems before they become failures. Instead of waiting for a breakdown or replacing parts on a fixed schedule, technicians collect data from equipment while it is operating and compare those readings to known-good baselines or manufacturer limits. When a reading drifts out of range, the team investigates and acts — before a bearing seizes, a motor burns up, or a pump seal fails.

This lesson prepares you to participate in an actual PdM round at your externship site, collect data using real instruments, interpret what you find, and communicate your results in a professional field report.

Why Condition Monitoring Matters

Rotating equipment — motors, pumps, compressors, gearboxes, fans — and fluid-handling systems degrade gradually. The early signs of that degradation show up as changes in vibration level, heat, sound, or lubricant condition long before a failure is visible or audible to an untrained worker. A structured condition-monitoring program turns those subtle signals into actionable data, extending equipment life and reducing unplanned downtime. In manufacturing and marine environments, unplanned downtime can halt an entire production line or leave a vessel unable to operate safely.

Four Common Monitoring Techniques

Vibration analysis measures how much a machine or its bearing housing is moving. A healthy, well-aligned machine vibrates within a predictable, low amplitude. A worn bearing, misaligned shaft, unbalanced impeller, or loose mounting will each produce a distinctive change in vibration level or frequency. Technicians measure overall vibration amplitude in inches per second (in/s) or millimeters per second (mm/s) at marked points on the equipment. Readings are compared to the manufacturer's specification or the site's established baseline.

Infrared thermometry and thermal imaging detect surface temperature without contact. Overloaded electrical connections, failing bearings, and over-lubricated or under-lubricated components all run hotter than normal. An infrared thermometer gives a single spot reading; a thermal camera shows the whole temperature map. Either way, you compare the reading to adjacent similar components and to the manufacturer's rated operating temperature or the site's normal-range record.

Ultrasonic detection uses a hand-held sensor sensitive to high-frequency sound (typically in the ultrasonic range) that the human ear cannot hear. It is effective for detecting air and gas leaks, steam trap failures, bearing defects, and arcing in electrical equipment. The technician listens through headphones or watches a decibel meter while scanning the sensor across the equipment. A characteristic change in sound quality or a rising dB reading indicates a problem.

Oil and fluid condition monitoring involves taking a small sample of lubricating oil or hydraulic fluid and evaluating it — either by sending it to a laboratory for full analysis or by using an on-site visual check or test kit. Indicators include color change, cloudiness (water contamination), metal particle content, and viscosity change. On marine vessels and in heavy manufacturing, regular oil sampling on gearboxes and hydraulic systems is a standard practice.

Collecting Data Correctly

Accurate data starts before you touch any instrument. Record the equipment tag number, nameplate data (manufacturer, model, rated speed, rated power), measurement location (for vibration: drive-end bearing, non-drive-end bearing, vertical/horizontal/axial), date, time, and ambient conditions. Use the site's established measurement points — many facilities mark them with paint dots or labels so readings are taken in exactly the same spot every time, making trending reliable.

Follow the instrument manufacturer's instructions for zeroing, calibrating, or coupling the sensor. Hold a contact vibration probe firmly and squarely against the measurement point; allow readings to stabilize before recording. For infrared readings, be aware of surface emissivity — shiny metal surfaces can give falsely low readings; use emissivity correction settings or a piece of matte tape as directed by site procedure.

Record every reading in the Field Log immediately — do not rely on memory. Note any unusual observations: abnormal noise, leaks, loose guards, or visible damage.

Comparing Readings to Limits

Once data is collected, compare each reading to the reference value — either the manufacturer's published limit, the site's established baseline, or both. If the site has a trending chart, plot your new reading to see the direction of change. A reading that is higher than baseline but still within the acceptable limit is worth watching; a reading that exceeds the limit requires a documented response. Common responses are: continued monitoring at a shorter interval, a work order generated for inspection or repair, or no action with a documented rationale (for example, a brief temperature spike that returned to normal).

Discuss any out-of-range finding with your supervising technician before leaving the area. Never alter recorded data to make a reading look acceptable.

Safety During PdM Rounds

Equipment is running during condition monitoring — that is the point. Keep hands, tools, and clothing clear of rotating parts at all times. Tie back hair and secure loose clothing. Never remove machine guards to get a measurement; use the correct probe length or instrument setting to reach measurement points safely. If infrared work involves open electrical panels, confirm that the proper arc-flash PPE and an energized electrical work permit are in place per site policy and NFPA 70E requirements before approaching. For ultrasonic scanning near steam or pressure lines, be aware of burn and pressure hazards. If an oil sample requires isolating a sample port, follow site lockout/tagout (LOTO) procedures if any portion of the system must be de-energized or depressurized first.

Writing the Field Report

Your Condition Monitoring Field Report translates raw data into a professional communication. Use the program template. Include a data table with equipment ID, measurement type, location, recorded value, reference limit, and status (normal / monitor / action required). Write clear conclusions — what does the data suggest about the condition of each piece of equipment? State recommended next steps. Reference at least one manufacturer specification or site standard by name. Write in plain, complete sentences. Have your supervising technician review and countersign the report before you submit it.

A well-written field report demonstrates the same skill reliability engineers use every day: turning numbers into decisions.

Key terms10

Predictive maintenance (PdM)A strategy that uses condition-monitoring data collected from operating equipment to forecast when maintenance is needed, allowing repair before failure occurs.
BaselineA set of condition-monitoring readings taken from equipment when it is known to be in good operating condition; used as the reference for detecting future changes.
Vibration amplitudeThe magnitude of a machine's oscillating motion, commonly measured in inches per second (in/s) or millimeters per second (mm/s); an increase above baseline indicates a developing mechanical fault.
Infrared thermometryA non-contact temperature measurement technique that detects surface heat emission; used to identify overloaded electrical connections, failing bearings, and lubrication problems.
Ultrasonic detectionA condition-monitoring technique that senses high-frequency sound inaudible to the human ear; effective for locating leaks, steam trap faults, and early bearing defects.
Oil analysisLaboratory or field evaluation of a lubricant sample to assess contamination, wear-metal content, viscosity, and overall fluid condition as indicators of equipment health.
EmissivityA material property describing how efficiently a surface radiates heat compared to a perfect radiator; must be accounted for when taking infrared temperature readings, especially on shiny metal surfaces.
TrendingThe practice of plotting successive condition-monitoring readings over time to observe the direction and rate of change, enabling earlier warning of deterioration.
Work orderA formal written or electronic authorization directing maintenance personnel to perform a specific inspection, adjustment, or repair task on identified equipment.
Lockout/Tagout (LOTO)A mandated safety procedure (governed by OSHA 29 CFR 1910.147) requiring that energy sources be isolated and locked before any maintenance work that could expose workers to hazardous energy.

Worked examples4

1. A pump bearing housing is measured at 147 °F (63.9 °C). The manufacturer's specification states maximum continuous bearing temperature is 180 °F (82.2 °C), and the site baseline for this bearing is 118 °F (47.8 °C). Calculate the temperature rise above baseline and determine whether the reading is within the manufacturer's limit.
  1. Step 1 — Calculate rise above baseline: 147 °F − 118 °F = 29 °F above baseline.
  2. Step 2 — Compare to manufacturer limit: 147 °F is below the limit of 180 °F, so the reading does not exceed the manufacturer's specification.
  3. Step 3 — Interpret the trend: Although within the manufacturer's absolute limit, the bearing is running 29 °F above the established site baseline. A rise of this magnitude warrants flagging the reading in the Field Log, documenting it as 'monitor,' and discussing the finding with the supervisor for a possible shortened re-inspection interval.
Answer: The bearing temperature is 29 °F above site baseline but still 33 °F below the manufacturer's maximum limit of 180 °F. Correct action: flag as 'monitor,' document supervisor's guidance, and re-inspect at a shorter interval.
2. During a vibration round, three identical pump motors are measured at their drive-end bearing in the vertical direction. Readings are: Motor A = 0.10 in/s, Motor B = 0.28 in/s, Motor C = 0.11 in/s. The site acceptable limit is 0.25 in/s overall velocity. Which motor(s) require action, and by how much does each out-of-range motor exceed the limit?
  1. Step 1 — Compare each reading to the site limit of 0.25 in/s: Motor A (0.10) — within limit; Motor B (0.28) — exceeds limit; Motor C (0.11) — within limit.
  2. Step 2 — Calculate the amount Motor B exceeds the limit: 0.28 in/s − 0.25 in/s = 0.03 in/s over the limit.
  3. Step 3 — Record Motor B as 'action required' in the Field Log, note the overage of 0.03 in/s, and report to the supervising technician for a work-order decision.
Answer: Motor B at 0.28 in/s exceeds the site limit of 0.25 in/s by 0.03 in/s. Motors A and C are within limits. Motor B requires a work order or closer monitoring per supervisor direction.
3. An ultrasonic scan of a steam trap reads 74 dB. Adjacent healthy traps on the same line read between 52 dB and 58 dB. The site action threshold for steam trap scanning is any reading more than 10 dB above the average of similar healthy traps. Calculate whether the 74 dB trap exceeds the action threshold.
  1. Step 1 — Calculate the average dB of the two healthy reference traps: (52 + 58) ÷ 2 = 55 dB average.
  2. Step 2 — Determine the action threshold: 55 dB + 10 dB = 65 dB.
  3. Step 3 — Compare the suspect trap to the threshold: 74 dB > 65 dB, so the trap exceeds the action threshold by 74 − 65 = 9 dB.
  4. Step 4 — Record the finding as 'action required,' note the 9 dB overage, and discuss with the supervisor — a continuously blowing (failed-open) steam trap is a common cause of a sustained high dB reading.
Answer: The steam trap at 74 dB exceeds the site action threshold of 65 dB by 9 dB. It should be flagged for inspection and likely replacement; the supervisor should generate a work order.
4. An oil sample from a gearbox is taken. The site baseline color for this gear oil at the last change is amber/clear. The current sample appears dark brown and slightly cloudy. The oil lab report (where available) or visual chart interpretation lists dark color as indicating oxidation/thermal degradation and cloudiness as indicating possible water contamination. List the sequential steps a technician takes to document and act on this finding.
  1. Step 1 — Record the visual findings in the Field Log: color (dark brown versus baseline amber), clarity (cloudy versus clear baseline), sample date, equipment ID, oil type and viscosity grade, hours since last oil change.
  2. Step 2 — Compare observations to the site visual oil-condition chart or lab report interpretation guide; identify the two abnormal indicators (oxidation/degradation and possible water contamination).
  3. Step 3 — Flag both conditions as 'action required' in the Field Log and Field Report data table.
  4. Step 4 — Discuss findings with the supervising technician; document the supervisor's direction — likely options include sending the sample to a laboratory for full analysis, changing the oil at an earlier interval than scheduled, or investigating the source of water ingress (failed seal, condensation, cooler leak).
  5. Step 5 — Document the supervisor's response and any work order number in the Field Log before leaving the area.
Answer: Both discoloration (oxidation) and cloudiness (water contamination) are flagged as action-required findings. The supervisor's direction — which may include lab analysis, early oil change, and seal inspection — is documented in the Field Log and included in the Field Report with recommended next steps.

The math in this lesson2

Learners convert bearing temperatures between °F and °C and compare to the specified maximum.
N-Q.1S-ID.2
Brush up in the math halls at newSchoolWorks.com:
In class: Work alongside the supervising technician or a site reliability technician during scheduled predictive maintenance rounds; using the site's instruments (vibration meter, infrared thermometer, ultrasonic detector, or oil-analysis sample kit as available), collect baseline or trending data on at least four pieces of rotating or fluid-handling equipment, recording readings in the Field Log alongside equipment nameplate data, measurement location, date, and ambient conditions. · Compare collected readings to the manufacturer's acceptable ranges or site baseline records (where available); flag any reading outside normal range and discuss the finding with the supervisor, documenting the supervisor's interpretation and any follow-up action ordered (continued monitoring, work order generated, or no action with rationale). · Write a two-to-three-page typed Condition Monitoring Field Report summarizing the equipment surveyed, data collected, comparison to acceptable limits, conclusions, and recommended next steps; the report must include a simple data table, reference at least one manufacturer specification or site standard, and be reviewed and countersigned by the supervising technician before submission to the program coordinator.
Materials: Site vibration meter, infrared thermometer, or ultrasonic detector (as available); oil-analysis sample kit or visual oil-condition chart; manufacturer equipment manuals or site baseline data sheets; Field Log; program Condition Monitoring Field Report template; word-processing tool for report writing.
Check: Field Log entries show data collected from at least four equipment items with supervisor initials; Condition Monitoring Field Report scored by the program coordinator using a four-criterion rubric (data accuracy and completeness, correct comparison to limits, clarity of conclusions, professional writing/formatting) — student must score at least 3 out of 4 on every criterion to pass; report must bear the supervising technician's countersignature.

Practice check8

Answer each question, then check it. Nothing is recorded; this is your own practice.

Safety and Health
1. Before beginning a condition-monitoring round on operating rotating equipment, which safety action is MOST important?
Preventive and Predictive Maintenance
2. A technician records vibration readings at a motor drive-end bearing every month. Plotting the readings over six months shows a steady upward trend even though the latest reading is still below the site action limit. The BEST course of action is to:
Predictive Maintenance Tools and Instrumentation
3. When using an infrared thermometer on a shiny, unpainted metal motor housing, a technician should be aware that:
Lubrication and Fluid Analysis
4. In an oil sample taken from a hydraulic system, cloudiness or milky discoloration most commonly indicates:
Preventive and Predictive Maintenance
5. A student collecting condition-monitoring data records a vibration reading that appears to exceed the site action limit. The FIRST step after recording the reading is to:
Predictive Maintenance Tools and Instrumentation
6. Ultrasonic detection is particularly useful for identifying which of the following conditions on a steam distribution system?
Preventive and Predictive Maintenance
7. For condition-monitoring data to be useful for trending over time, measurements MUST be taken:
Technical Documentation and Reporting
8. A Condition Monitoring Field Report submitted to the program coordinator MUST include which of the following to be accepted for grading?
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