Definition
Reliability Engineering is the engineering discipline concerned with ensuring that products, assets and systems perform their required functions without failure for a specified period under defined operating and environmental conditions.
It combines failure analysis, probability, risk management, design decisions and lifecycle planning to improve dependability and reduce the likelihood and consequences of failure.
Human Explanation
Reliability Engineering is about making sure that something continues to work as expected over time and under the conditions in which it must operate.
Rather than waiting to repair failures, it investigates how and why failure can occur, how likely it is and how design, operation or maintenance strategy can reduce the risk.
The objective is dependable lifecycle performance, not only successful operation at the moment of delivery.
Why it Matters
A system that meets its requirements today but fails unpredictably during use may create safety, operational, financial and customer consequences.
Reliability Engineering helps reduce failures, improve availability and safety, control lifecycle cost and provide evidence-based confidence in continued performance.
Primary Focus
Its primary focus is understanding and engineering failure behaviour over time, including reliability, availability and maintainability under defined use, load and environmental conditions.
Disciplinary Boundary
Reliability Engineering is not the same as Maintenance, Maintenance Engineering or Asset Management. It is not limited to repairing equipment or scheduling maintenance after an asset enters operation.
It produces knowledge and engineering decisions about failure, life and dependability. Maintenance executes work to preserve or restore function, Maintenance Engineering develops maintenance solutions, and Asset Management balances asset value, risk and cost at organisational level. Reliability-Centred Maintenance is one method for defining maintenance requirements, not the whole discipline.
Typical Objectives
- Reduce failure probability and consequences
- Improve system reliability
- Increase availability
- Improve maintainability
- Reduce lifecycle cost
- Extend useful operational life
- Support system safety
- Support risk-informed decisions
Typical Methods & Tools
Depending on the system, lifecycle phase, operating conditions and reliability objectives, Reliability Engineering may apply methods such as:
- Failure Mode and Effects Analysis (FMEA)
- Fault Tree Analysis (FTA)
- Reliability Block Diagrams (RBD)
- Weibull Analysis
- Life Data Analysis
- Reliability Prediction
- Accelerated Life Testing
- Root Cause Analysis (RCA)
- Failure Reporting, Analysis and Corrective Action System (FRACAS)
- Reliability-Centred Maintenance (RCM)
- Condition and Failure Data Analysis
Methods are selected according to the failure question, available evidence and lifecycle decision. Preventive or predictive maintenance may result from reliability analysis, but maintenance activity is not itself a substitute for Reliability Engineering.
Common Applications
- Aerospace
- Defence
- Automotive
- Rail systems
- Energy generation and distribution
- Oil and gas
- Medical devices
- Pharmaceutical manufacturing
- Industrial automation
- Critical infrastructure
Relationship to Other Engineering Disciplines
Reliability Engineering provides lifecycle failure knowledge that informs system architecture, product design, manufacturing controls, production continuity and operational decisions.
- Quality Engineering
- Concentrates on consistent fulfilment of requirements and defect prevention; Reliability Engineering concentrates on required performance and failure behaviour over time.
- Systems Engineering
- Integrates reliability requirements, interfaces and evidence into system architecture and lifecycle decisions.
- Manufacturing Engineering
- Uses reliability knowledge to prevent manufacturing-induced failure mechanisms and create capable production equipment.
- Production Engineering
- Uses equipment reliability and availability information when planning flow, capacity and production continuity.
- Industrial Engineering
- Connects asset and system dependability with wider operational performance, resource decisions and system resilience.
- Human Factors Engineering
- Examines human interaction, use and error conditions that can influence system dependability and recovery.