Failure Modes Effects and Criticality Analysis - FMECA

How to generate a Failure Modes Effects and Criticality Analysis (FMECA) using our platform, background and common questions.

How to produce a FMECA using modla

Generating FMECAs is a quick and easy three-step process:

  1. Choose the appropriate asset class.
  2. Customize the asset's specific inputs including conditional and environmental considerations. Consequences of failure specific to your business can be imported including monetised risk values.
  3. Select and run a FMECA analysis, then download the report.

Extracting a FMECA from our platform is this fast

What is a FMEA or FMECA?

FMEA was developed by the United States military in the 1940s as a risk identification tool. From FMEA, the Failure Modes, Effects and Criticality (FMECA) analysis was born. The new methodology incorporated a criticality analysis to rank failure modes in their order of importance.

A FMECA captures the links between the way an asset fails and the impact of its failure on the business. Historically, FMEA was used during the design phase of a project, to identify and rectify potential failures before going into production. However, understanding the relationship between failure modes and their effects is a key component to making decisions relating to an asset’s operation and maintenance. Nonetheless, a FMEA or FMECA is only part of the necessary information to make informed decisions and should not be considered in isolation.

Nowadays, FMEAs and to a greater degree, FMECAs are used to inform and improve maintenance efforts throughout the life of an asset. Failure mode and effects relationships typically form the basis of more advanced methodologies such as Reliability Centered Maintenance (RCM). More progressive analyses (such as modla's platform) combine FMEA structures with statistical distributions to predict likelihoods of specific failure modes. This enables users to produce results for probabilistic scenarios with varying maintenance, operational and intervention strategies.

What is a failure mode?

failure mode describes a way in which a system or component may fail, meaning it can no longer perform its function.

Effects describe the impacts of a failure on the business, environment, stakeholders or otherwise. They answer the question: “If this asset fails in this way, what happens?”

The analysis puts forth a structured or stepwise method in which the FMEA/FMECA is carried out by identifying failure modes of a process or product, as well as their impacts.

Criticality (optional) identifies the asset's importance to the business. There are two main schools of thought:

  1. Criticality should be ranked by consequence, or
  2. Criticality should include a probability component and be ranked by risk.

What are the main components of a FMECA?

The main components of performing a FMEA/FMECA are:

  • Detail the failure modes, and effects
  • Determine the severity level or consequence
  • Determine the probability of consequence if a failure occurs
  • Determine the probability of failure
  • Calculate and rank the criticality

Modla's platform can produce FMECAs based on a probabilistic analyses that incorporates your specific environmental and operational nuances.

What is criticality and why do different definitions exist?

For some, criticality is simply the consequence of failure regardless of its associated likelihood. This approach was historically used to rank consequences such as safety incidents, which at the time, were largely qualitative.

In recent years, more and more businesses are turning to quantitative assessments of risk and monetising everything from environmental impacts, to the stakeholder and reputational loss. This can be achieved by using a corporate value framework.

To understand which approach to use, the question must be asked: “Why are we trying to rank our assets in the first place?”

If the reason is to understand potential outcomes and make sure that each has a mitigating task or control in place, then a consequence only approach is suitable since this is a binary decision i.e is the outcome acceptable or not?

The problem with this approach is that businesses usually have finite resources, and trade-offs must be made. Are you willing to bankrupt the business in order to prevent an environmental spill? Probably not. Are you willing to spend a few thousand dollars? Probably. The spectrum of cost-benefit is what needs to be understood to make better decisions than the black and white decisions of the past.

The more information we have, the better decisions we can make. The likelihoods of failure is thus a valuable addition to the ranking process.

Conversely, criticality can be defined as a measure of risk. Risk includes statistical probabilities and is defined as:

Risk = probability * consequence

By using the risk definition for criticality, better decisions can be made by understanding both the likelihood and consequence of an event. For example, high probability, low consequence events can still produce a large risk (think employees slipping and tripping). This school of thought is particularly applicable to industries with high volumes of assets, but with low probabilities of failure (e.g. electricity transmission, where there are millions of poles and conductors). Since risk is summative, the approach is scalable.

Modla moves away from the risk matrix classifications of probabilities of failure and consequences. This approach treats risk as a spectrum, and not discrete levels.

How do I calculate consequence and probabilities?

Following on from the formula, risk = probability * consequence, we can expand this to:

Risk due to a specific failure mode = probability of failure mode occurring * (probability of consequence 1 * consequence 1 + ... + probability of consequence n * consequence n)

The presence of a specific failure mode is dependent on the asset in question. Similarly, the probability of the consequence is dependent on the context of the asset e.g. where is it located and are there redundancies in place. Both the probability and consequence calculation may take into account:

  1. Environmental variables (e.g. corrosion)
  2. Operational variables (e.g. duty)
  3. Asset specific variables (e.g. configuration)
  4. Conditional variables (e.g. vibration)

When should I use a criticality analysis?

There are several benefits to FMEA/FMECAs, and its structure is a key building block our Reliability Centered Maintenance + Decisions (RCMD) methodology.

Apart from compliance with various safety and quality requirements e.g. ISO 9001, ISO/TS 16949, Six Sigma, QS 9000, FDA Good Manufacturing Practices (GMPs), FMECAs capture engineering knowledge which can inform troubleshooting efforts, identification of maintenance tasks and more.

To paint a complete picture, the FMECA must be combined with other information such as maintenance task costs and resource information in order to improve maintenance and operational strategy.

The FMECA structure, as well as other causality information, forms the basis of modla's knowledge base (see knowledge management). A criticality analysis should be performed on every asset. However, the main barrier to its wider adoption is the cost (monetary and resources). Modla's platform reduces the cost to perform a FMECA to the point where it is no longer cost-prohibitive to perform a FMECA on all assets.

FMEA/FMECAs are of fundamental importance to maintenance teams. It can be used to improve the reliability of assets during the design phase and improve performance long after by optimising strategies and capturing engineering knowledge. FMECAs allow businesses to review the criticality of competing failure modes and to prioritize the application of resources. However, the quality of this analysis is highly dependent on the quality of the associated data and knowledge used as inputs.