FMEA: Failure Mode and Effects Analysis

Understanding FMEA: A Systematic Approach to Risk Prevention

In the competitive landscape of product development, identifying potential failures before they occur is not merely advantageous—it is essential. Failure Mode and Effects Analysis (FMEA) represents one of the most powerful tools available to engineering teams seeking to design reliable, safe, and cost-effective products. For manufacturers and product developers across Atlantic Canada, mastering FMEA methodology can mean the difference between market success and costly recalls.

FMEA is a structured, systematic technique for failure analysis that originated in the aerospace industry during the 1960s and has since become a cornerstone of quality engineering across virtually every manufacturing sector. From the automotive plants of Ontario to the marine equipment manufacturers throughout Nova Scotia and the Maritimes, FMEA provides a common language and framework for identifying, prioritising, and mitigating risks throughout the product development lifecycle.

At its core, FMEA asks three fundamental questions about every component, process, or system: What could go wrong? What would happen if it did? And how can we prevent it? By systematically answering these questions, engineering teams can allocate resources effectively, improve design robustness, and demonstrate due diligence in their development processes.

Types of FMEA and Their Applications

Understanding the different types of FMEA is crucial for selecting the appropriate methodology for your specific application. Each type serves a distinct purpose in the product development and manufacturing process.

Design FMEA (DFMEA)

Design FMEA focuses on potential failure modes that could result from design deficiencies. This analysis is typically conducted during the early stages of product development, ideally before design finalisation. DFMEA examines how design choices might lead to failures during the product's intended use, considering factors such as material selection, geometric tolerances, and interface compatibility.

For example, a Nova Scotia-based manufacturer developing marine navigation equipment would use DFMEA to analyse potential failures related to saltwater corrosion, temperature cycling in harsh Atlantic conditions, and electromagnetic interference from vessel electrical systems. The analysis would identify critical design parameters that require additional testing or alternative material specifications.

Process FMEA (PFMEA)

Process FMEA analyses potential failures in manufacturing and assembly processes. This type of FMEA is particularly valuable for identifying process variables that could introduce defects, even in well-designed products. PFMEA typically begins after the design is substantially complete and manufacturing processes are being developed.

Maritime manufacturers often face unique process challenges, including humidity control in coastal facilities, temperature variations in seasonally heated buildings, and supply chain considerations related to geographic isolation. PFMEA helps identify these region-specific process risks and develop appropriate controls.

System FMEA (SFMEA)

System FMEA takes a higher-level view, analysing potential failures at the system or subsystem level. This approach is particularly valuable for complex products where multiple components interact, and where failures in one subsystem could cascade through the entire system. SFMEA is often used in conjunction with functional block diagrams and interface analyses.

The FMEA Process: A Step-by-Step Methodology

Conducting an effective FMEA requires a disciplined approach and cross-functional collaboration. The following steps outline the standard methodology used by engineering teams worldwide.

Step 1: Define the Scope and Assemble the Team

Begin by clearly defining the boundaries of the analysis. What product, process, or system will be analysed? What assumptions will be made? The FMEA team should include representatives from design engineering, manufacturing, quality assurance, and often procurement and service functions. A typical FMEA team comprises four to eight members with diverse perspectives and expertise.

Step 2: Develop the Function and Requirements List

Document all functions that the item under analysis must perform. For each function, identify the associated requirements and specifications. This step establishes the baseline against which potential failures will be evaluated. Functions should be stated using clear, action-oriented language such as "transmit torque of 150 Nm minimum" or "maintain seal integrity at pressures up to 500 kPa."

Step 3: Identify Potential Failure Modes

For each function, brainstorm all ways in which the function could fail to be performed. Failure modes should be specific and technical. Rather than stating "part breaks," specify "fatigue fracture at stress concentration," "corrosion-induced wall thinning," or "creep deformation under sustained load." Historical warranty data, service reports, and similar product experience provide valuable input for this step.

Step 4: Determine Effects and Causes

For each failure mode, identify the potential effects on the customer, the next operation, or the overall system. Effects should describe what the customer would experience or observe. Similarly, identify the root causes or mechanisms that could lead to each failure mode. Most failure modes have multiple potential causes, and each cause should be analysed separately.

Step 5: Assign Severity, Occurrence, and Detection Ratings

This step introduces the quantitative aspect of FMEA through three rating scales, typically scored from 1 to 10:

• Severity (S): Rates the seriousness of the effect, with 1 representing no discernible effect and 10 indicating a safety hazard without warning

• Occurrence (O): Estimates the likelihood of the cause occurring, with 1 representing extremely unlikely (less than 1 in 1,000,000) and 10 indicating near certainty (greater than 1 in 10)

• Detection (D): Assesses the ability of current controls to detect the failure mode or cause before reaching the customer, with 1 meaning the control will almost certainly detect the issue and 10 indicating no known control method

Step 6: Calculate the Risk Priority Number

The Risk Priority Number (RPN) is calculated by multiplying the three ratings: RPN = S × O × D. This produces a value ranging from 1 to 1,000, with higher numbers indicating greater risk priority. While the RPN provides a useful ranking mechanism, it should not be the sole criterion for action. Items with high severity ratings warrant attention regardless of their overall RPN.

Step 7: Develop and Implement Actions

For high-priority items, develop recommended actions to reduce risk. Actions may target any of the three rating factors: reducing severity through design changes, reducing occurrence through robust design or process controls, or improving detection through enhanced testing or inspection. Assign responsibility and target completion dates for each action.

Best Practices for Effective FMEA Implementation

The value derived from FMEA depends significantly on how well it is executed. The following best practices help ensure meaningful results.

Start Early and Update Continuously

FMEA is most valuable when begun early in the development process, ideally during concept development. At this stage, design changes are relatively inexpensive and can be implemented without significant schedule impact. However, FMEA should be treated as a living document, updated as the design evolves, new information becomes available, or field experience reveals previously unknown failure modes.

Use Consistent Rating Criteria

One of the most common pitfalls in FMEA is inconsistent application of rating scales. Develop company-specific rating guidelines with clear examples relevant to your products and processes. Document these guidelines and train all FMEA participants to ensure consistent application across projects and teams. Many Canadian manufacturers align their criteria with automotive industry standards such as those published by the Automotive Industry Action Group (AIAG).

Focus on Action, Not Documentation

An FMEA that identifies risks but fails to drive corrective action provides limited value. Establish clear criteria for when action is required, such as RPNs exceeding 100 or severity ratings of 9 or 10. Track action completion and verify effectiveness through updated ratings. The goal is risk reduction, not paperwork completion.

Leverage Cross-Functional Expertise

The most effective FMEAs draw upon diverse perspectives. Design engineers understand intended functionality, manufacturing personnel understand process capabilities, quality engineers understand inspection and testing limitations, and service technicians understand field failure patterns. Bringing these perspectives together produces more comprehensive and realistic analyses.

FMEA in Regulatory and Quality Management Contexts

For many industries, FMEA is not merely a best practice but a regulatory or contractual requirement. Understanding these requirements is essential for manufacturers serving regulated markets.

In the medical device industry, Health Canada and the Canadian Medical Devices Regulations require manufacturers to establish and maintain procedures for risk analysis. While the regulations do not mandate FMEA specifically, the technique is widely recognised as meeting the intent of ISO 14971 for risk management of medical devices. Many notified bodies and regulatory reviewers expect to see FMEA as part of the design history file.

The aerospace industry, significant to Atlantic Canada's manufacturing sector, requires FMEA under AS9100 quality management system standards. Similarly, automotive suppliers must conduct FMEA as part of the Advanced Product Quality Planning (APQP) process mandated by major original equipment manufacturers.

Beyond regulatory requirements, FMEA supports ISO 9001:2015 requirements for risk-based thinking. The standard requires organisations to determine risks and opportunities that need to be addressed, and FMEA provides a structured methodology for meeting this requirement in product development contexts.

Common Challenges and How to Overcome Them

Despite its proven value, FMEA implementation often encounters obstacles. Recognising and addressing these challenges improves the likelihood of successful adoption.

Resource and Time Constraints

Thorough FMEA requires significant time investment, particularly for complex products. Engineering teams under schedule pressure may be tempted to rush through the analysis or skip it entirely. Combat this tendency by integrating FMEA into project schedules from the outset, allocating appropriate resources, and demonstrating the cost-benefit through tracking of issues avoided. Studies consistently show that problems identified during FMEA cost 10 to 100 times less to address than those discovered in production or the field.

Lack of Historical Data

New product categories or novel technologies may lack the historical failure data that informs effective FMEA. In these cases, teams must rely more heavily on engineering analysis, testing, and expert judgement. Consider conducting accelerated life testing, consulting published reliability data for similar components, or engaging external specialists with relevant experience. Maritime engineering projects, for instance, can often leverage extensive databases of marine equipment failures maintained by classification societies.

Analysis Paralysis

Some teams become overwhelmed by the potential scope of FMEA, attempting to analyse every conceivable failure mode at extreme levels of detail. Maintain focus by clearly defining scope boundaries, using appropriate levels of system decomposition, and applying the 80/20 principle—typically, a small number of failure modes account for the majority of risk. Concentrate analytical effort where it provides the greatest benefit.

Integrating FMEA with Other Engineering Tools

FMEA is most powerful when integrated with complementary engineering and quality tools. Design of Experiments (DOE) can optimise critical parameters identified through FMEA. Fault Tree Analysis (FTA) provides a top-down perspective that complements FMEA's bottom-up approach. Statistical Process Control (SPC) monitors the manufacturing parameters flagged as critical through Process FMEA.

Digital tools increasingly support FMEA activities, with specialised software enabling efficient data management, automatic RPN calculation, action tracking, and report generation. For small and medium enterprises throughout Nova Scotia and the Atlantic provinces, cloud-based FMEA solutions offer enterprise-level capabilities without significant infrastructure investment.

Partner with Sangster Engineering Ltd. for Your FMEA Needs

Effective FMEA requires not only methodological knowledge but also deep engineering expertise and practical experience across diverse applications. At Sangster Engineering Ltd., our team brings decades of combined experience in product development, quality engineering, and risk analysis to every client engagement.

Based in Amherst, Nova Scotia, we understand the unique challenges facing manufacturers in Atlantic Canada—from the harsh environmental conditions that test product durability to the supply chain considerations that influence design decisions. Whether you are developing a new product, improving an existing design, or seeking to enhance your manufacturing processes, we can help you implement FMEA effectively and efficiently.

Contact Sangster Engineering Ltd. today to discuss how our professional engineering services can support your product development initiatives. From initial FMEA training for your team to comprehensive design reviews and risk analyses, we provide the technical expertise and practical guidance you need to bring reliable, successful products to market. Let us help you identify and eliminate potential failures before they become costly problems.

Partner with Sangster Engineering

At Sangster Engineering Ltd. in Amherst, Nova Scotia, we bring decades of engineering experience to every project. Serving clients across Atlantic Canada and beyond.

Contact us today to discuss your engineering needs.