Work management
Reliability guide
What does a reliability engineer do?
The people, methods, and everyday decisions behind equipment that performs when needed.
CCanary teamSep 30, 2026Updated Oct 1, 20269 min readReliability
What is a reliability engineer?
A reliability engineer studies how equipment fails and helps a team make it perform its required function, under defined operating conditions, for the time it is needed.
In a plant, that means connecting engineering analysis with the work happening on the floor. The engineer looks at failure history, operating conditions, maintenance practices, and equipment design. The useful outcome is a decision: change a task, correct an installation, prepare a spare, or redesign a weak point.
Picture a production pump that returns to the repair shop every few weeks. Each repair restores service. The reliability question is what keeps damaging it, what evidence would establish the cause, and what needs to change before the next failure.
This guide covers reliability engineering for physical equipment in manufacturing, processing, and facilities. Reliability depends on how an asset is operated and maintained as well as how it is designed. Operators, technicians, planners, and engineers all contribute evidence.
What does the job involve?
A useful reliability program follows the whole job: identify a problem, understand its consequence, prepare the response, and check the result. The engineer helps connect those steps.
- Make priorities explicit. Identify equipment whose loss affects people, the environment, product quality, or production. A standby pump and the only pump feeding a line may need different maintenance strategies.
- Investigate recurring losses. Review failed parts, operating records, technician observations, and recent changes. Separate an observed symptom from a proposed cause, and record what remains uncertain.
- Review maintenance tasks. Ask which failure mode each inspection or replacement addresses. Define what the technician should check, the acceptable condition, and the response when a finding falls outside it.
- Turn findings into prepared work. Agree on the scope, procedure, parts, access, skills, and acceptance checks with the people doing the job. An analysis needs an owner and a route onto the schedule.
- Improve equipment decisions. Bring failure experience into equipment specifications, component selection, installation standards, and spare-parts planning. Consider repair access and lead times alongside purchase cost.
- Follow up after the change. Check the asset under comparable operating conditions. Record whether the fault returned and whether the change created another problem. Update the job plan with what the team learned.
Reliability engineer vs. maintenance engineer
The roles overlap, and titles vary by organization. Both can investigate failures, improve designs, and develop maintenance plans. The distinction is usually where each person spends most of their attention.
| Focus | Reliability engineer | Maintenance engineer |
|---|---|---|
| Typical question | What changes will make this equipment perform more consistently? | How should we maintain, troubleshoot, and restore this equipment? |
| Common work | Failure patterns, risk reviews, strategy changes, and improvement verification. | Technical repair support, job methods, maintenance execution, and equipment modifications. |
| Shared responsibility | Provide evidence and define the change with the team. | Help make the change practical and capture what happened during the work. |
Choose a method for the question
Start with the decision you need to make. A short investigation with sound evidence can be more useful than a complex model built on inconsistent records.
- Failure modes and effects analysis (FMEA). Use it to examine how a function could fail, what the effects would be, and which actions deserve attention. Bring operations and maintenance into the review. Risk scores support judgment; a single combined score can hide an important consequence.
- Reliability-centered maintenance (RCM). Work from required function, failure mode, and consequence to an appropriate response. That may be a condition check, a scheduled task, a test of a protective function, or a design change. Deliberate run-to-failure requires acceptable consequences and a recovery plan.
- Root cause analysis (RCA). Use an event timeline and physical evidence to test explanations for a failure. Five Whys and cause-and-effect diagrams can organize the investigation. Assign corrective actions and check their effectiveness; a completed diagram alone does not establish a cause.
- Condition monitoring. Vibration, oil analysis, thermography, and ultrasound can reveal particular developing faults. Match the technique and inspection interval to the failure mode and the time available to respond. Include who reviews a finding and how the resulting work gets prepared.
- Life-data and system analysis. Weibull analysis can help explore time-to-failure patterns when the data and assumptions fit. Record exposure and assets that have not failed, too. Fault trees help examine combinations of events behind a system-level loss. Use specialist support when the consequence or model complexity warrants it.
A pump that keeps coming back
Consider this hypothetical example: a process pump has repeated bearing failures. The work history records several bearing replacements, but little about operating load, alignment, lubrication, or the condition of the removed parts.
- Define the loss. Agree on the pump’s required flow and duty. Establish which events count as failures and what they interrupted. Collect the repair dates, operating hours, observations, and available condition readings.
- Test plausible explanations. The team considers contamination, lubrication, loading, and alignment. It inspects the removed bearing and checks installation records. Suppose physical checks find pipe strain and a change in alignment after the piping is connected.
- Prepare the corrective work. The engineer and maintenance team agree on a piping-support correction and alignment checks under the appropriate conditions. The planner prepares the parts, procedure, qualified labor, isolation requirements, and return-to-service checks.
- Capture what was done. The completed work order records the finding, the correction, the measurements, and the acceptance result. “Bearing replaced” would leave the next person missing the most useful part of the story.
- Check the result over time. Follow the pump under comparable duty and review whether the fault recurs. Choose a review period that reflects its previous failure pattern. Carry the confirmed lesson into installation checks for similar equipment.
Measure performance with clear boundaries
Choose a small set of measures that answers a real question. Write down the asset population, observation period, event definition, and time boundaries before comparing results.
| Measure | Calculation | What to watch |
|---|---|---|
| Mean time between failures (MTBF) | Recorded operating time ÷ counted failures, for repairable equipment. | Compare similar duty and failure definitions. An average is not a countdown to the next failure. |
| Mean time to repair (MTTR) | Total active repair time ÷ completed repairs, using an active-repair definition. | State whether diagnosis, testing, and delays are included. Track total restoration time separately when it includes waiting. |
| Observed availability | Uptime ÷ (uptime + downtime) within the defined observation window. | State how planned stops, standby time, and periods with no production demand are treated. |
| Repeat failures | Count of the same defined failure mode recurring within an agreed period. | Use the same equipment scope and recurrence window. Review the underlying events, not just the total. |
Read the event behind the average
For a hypothetical repairable pump, 1,200 operating hours and three counted failures give an observed MTBF of 400 hours. That number describes the recorded period. It does not mean the next bearing will last 400 hours, and three events provide limited evidence about a long-term failure pattern.
Pair lagging measures with evidence of follow-through: corrective actions completed, inspections that produce usable findings, and work orders with meaningful closeout notes. A higher completion count is useful only if the work addresses the right failure modes.
Skills that make the analysis useful
Equipment knowledge gives an investigation context. Learn how the process runs, what the asset must deliver, and how its components wear or fail. Spend time with operators and technicians; changes in sound, load, temperature, and repair history often shape the next question.
Data skills help you test that question. Be comfortable checking timestamps, grouping failure modes, calculating exposure, and identifying gaps in a dataset. Statistical techniques become useful when their assumptions match the equipment and the records.
Communication turns the finding into action. Explain the evidence, uncertainty, proposed work, and acceptance criteria in terms the planner, technician, and operations lead can use. Keep the technical detail that changes a decision.
Education and certification paths
People enter the field through engineering education, maintenance experience, or a combination of the two. The requirements depend on the employer and the work. Build a portfolio of investigations, task reviews, and improvements whose results you can explain.
SMRP’s Certified Maintenance & Reliability Professional (CMRP) covers business and management, manufacturing process reliability, equipment reliability, organization and leadership, and work management. ASQ’s Certified Reliability Engineer (CRE) addresses reliability engineering knowledge and methods.
Use the credential providers’ current guidance to check eligibility, examination scope, and recertification requirements. Select training around the work you need to become better at doing.
A practical first-month plan
For a new role or a small reliability program, start with one equipment group and one recurring loss. This is a suggested sequence, not a promise to resolve every failure in 30 days.
- Week 1: understand the work. Walk the process with operations and maintenance. Agree on required functions, critical consequences, and one problem worth investigating. Locate the asset history and listen to the people who maintain it.
- Week 2: establish the evidence. Build an event timeline. Reconcile work orders with downtime and operating records. Note missing information and arrange the checks needed to distinguish plausible causes.
- Week 3: prepare a response. Review the evidence with the team. Choose an action, assign an owner, and define acceptance criteria. Prepare the work or schedule further investigation if the cause remains uncertain.
- Week 4: agree on follow-up. Record completed changes and outstanding actions. Establish when and how to review equipment performance. Keep monitoring long enough to judge the result under representative conditions.
Where the CMMS fits
A computerized maintenance management system (CMMS) can hold the work record that a reliability program depends on. The team still supplies the engineering judgment: what failed, why the evidence matters, and which change is justified.
Make each completed job useful to the next person. Capture the asset, operating condition, observed fault, work performed, parts used, checks completed, and any follow-up. Keep a suspected cause distinct from a confirmed finding.
Use that history when preparing the next work order and reviewing preventive tasks. The connection between observation, prepared work, and a recorded result is where a reliability program becomes part of daily maintenance.
Frequently asked questions
- What does a reliability engineer do each day? The mix varies: review failures and condition findings, inspect equipment, meet with operators and technicians, analyze records, and help prepare or verify improvement work.
- Is reliability engineering only predictive maintenance? Predictive and condition-based methods are part of the toolkit. The role also covers failure analysis, maintenance-task selection, design feedback, operating practices, and follow-up.
- Can a small team do reliability work? Yes. A maintenance engineer or experienced team member may own it. Start with a bounded problem, useful records, and protected time to investigate and follow through.
- How do you know the work helped? Check whether the targeted failure or loss changed under comparable conditions, whether the action was actually implemented, and whether the improvement persisted. Document uncertainty and other changes that could explain the result.
Further reading
The operating approach in this guide also draws on Ramesh Gulati’s Maintenance and Reliability Best Practices (2009). The examples are illustrative; no customer results or industry benchmarks are presented. The ASQ, SMRP, and Department of Energy links above provide additional method and certification guidance.
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