FMECA Criticality Matrix

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What is FMECA Criticality Matrix?

FMECA criticality matrix is a powerful tool that can help you identify and prioritize potential failure modes in your systems. It can also help you understand the relationships between different failure modes and their impact on system performance.

In essence, FMECA criticality matrix is a graphical representation of the relative impact of failure modes on system performance. By plotting different failure modes according to their impact, an organization can get a clear picture of where their efforts need to be focused in order to ensure overall system reliability.

Why is FMECA Criticality Matrix Used?

The criticality matrix is one of the most powerful tools in the FMECA technique. It can be used to determine the importance of individual components or systems, and identify potential problems that could lead to a failure.

The matrix is divided into four quadrants, with each quadrant representing a different level of criticality. The first quadrant is for components that are essential to the operation of the system and must be constantly monitored. The second quadrant is for components that are important, but can be allowed to fail without major consequences. The third quadrant is for components that are not essential, but their failure could cause significant problems. The fourth quadrant is for components that are not essential and their failure would not cause any major problems.

Each component or system is assigned a score based on its significance to the operation of the overall system. The higher the score, the more important the component or system. By using this information, engineers can prioritize which components or systems need to be monitored more closely and which can be allowed to fail without major consequences.

This tool is particularly useful in risk management because it helps identify potential risks before they become actual problems. By using the matrix, engineers can develop contingency plans for how to deal with failures when they do occur. This technique can also be used to improve designs by identifying areas where improvements can be made to reduce the likelihood of failures occurring in the first place .

What Are The Steps Involved in Using FMECA Criticality Matrix?

In order to use an FMECA criticality matrix, there are a few steps involved.

First, identify the system under consideration and list all of its subsystems and components.

Then, for each subsystem and component, list the potential failures that could occur.

Once all potential failures have been identified, rate the severity of each one using a scale of 1-10, with 1 being the least severe and 10 being the most severe.

Next, rate the likelihood of each failure occurring on a scale of 1-10, with 1 being the least likely and 10 being the most likely.

Calculate the criticality index for each failure by multiplying its severity rating by its likelihood rating.

The criticality index can then be used to prioritize corrective action items.

What Is The RPN in FMECA?

The RPN, or Risk Priority Number, is a key metric in FMECA that assigns a numerical value to each potential failure mode based on its Severity, Occurrence, and Detection ratings. This number is then used to prioritize corrective actions and preventive measures.

The RPN is calculated by multiplying the Severity, Occurrence, and Detection ratings for each failure mode. The resulting number is then used to rank the failure modes from most critical to least critical. The most critical failure modes will have the highest RPNs and should be addressed first.

Severity: How serious is the potential impact of the failure mode? (1 = minor, 5 = catastrophic)

Occurrence: How often will the failure mode occur? (1 = rare, 5 = continuous)

Detection: How easily can the failure mode be detected? (1 = difficult, 5 = easy)

For example, let’s say we have two potential failure modes:

  • Mode 1: A power supply unit fails, causing a loss of data.

Severity: 4 Occurrence: 2 Detection: 3 RPN: 4 x 2 x 3 = 24

  • Mode 2: A cable is loose, causing an intermittent loss of data.

Severity: 3 Occurrence: 4 Detection: 2 RPN: 3 x 4 x 2= 24

In this example, both modes have an RPN of 24.


RPN is short for Risk Priority Number and is a critical metric in FMECA. It is a measure of the relative risk of each failure mode, taking into account both the Severity and Occurrence ratings. The higher the RPN, the greater the risk.

To get an accurate picture of the risks associated with each failure mode, it is important to consider both Severity and Occurrence ratings. A high Severity rating but low Occurrence rating might indicate a rare but catastrophic failure mode, while a low Severity rating but high Occurrence rating might indicate a less serious but more common failure mode.

In general, failures with high RPNs should be given priority when addressing risks associated with a system or product. By identifying and addressing these critical failures first, we can minimize the overall risk to our systems and products.

What Are The Benefits of FMECA Criticality Matrix?

When it comes to analyzing and improving the design of systems, components, and processes, there is no tool more powerful than a Failure Modes and Effects Analysis (FMEA). FMEA allows you to systematically identify and evaluate potential failure modes and their effects on the system.

One of the most important aspects of an FMEA is the Criticality Matrix. The Criticality Matrix helps you prioritize failures by their Severity, Occurrence and Detection levels. By identifying failures that are high severity/low occurrence/low detection, you can focus your efforts on addressing these critical issues first.

There are many benefits to using a Criticality Matrix when conducting an FMEA :

  • Helps you identify which failures are most critical and need to be addressed first.
  • Enables you to more effectively utilize limited resources by focusing on high-priority items.
  • Makes it easier to track progress over time as you address each failure mode.
  • Provides a clear picture of the overall risk profile for the system under study.
  • Can be used to compare different designs or process options in order to choose the best option available.
  • Allows you to quickly identify potential failure modes that could lead to non-conformance or increased safety hazards.
  • Provides an objective metric for ranking and prioritizing potential solutions.

Overall, the Criticality Matrix is an effective tool for conducting a comprehensive FMEA that can help ensure the quality and safety of any system.

How to Use a Maturity Model or Failure Mode Effects Analysis with an FMECA to Augment its Effectiveness?

The relationship between a maturity model and FMECA is often misunderstood. In fact, they are complementary tools that can be used to achieve different objectives. While a maturity model helps identify the current state of development of a process or product, FMECA is used to proactively identify potential failure modes and their effects on the system.

When used together, these tools can provide a more comprehensive view of process or product development. By understanding both the current state and potential risks, organizations can make more informed decisions about where to allocate resources.

There are many different maturity models and failure mode effects analysis techniques available. The key is to select the ones that best fit the organization’s needs and objectives. With careful planning and execution, these tools can help unlock the power of FMECA criticality matrix .

What Are The Differences Between FMCA Matrix And HAZOP?

FMECA matrix is a tool used to evaluate the impact of failures on systems and components. It can be used to identify and prioritize corrective and preventive actions.

HAZOP is a technique used to identify potential hazards and operability problems in complex systems. It is often used in chemical plants and other industrial facilities.

The main difference between FMECA and HAZOP is that FMECA is used to identify the risks associated with component failures and HAZOP is used to identify potential safety risks and operability problems. FMECA focuses on analyzing failure mechanisms, while HAZOP is focused on system-level operational issues.

In other words :

  • FMECA is more holistic, looking at all possible failure modes while HAZOP focuses on specific hazards or operability problems.
  • FMECA takes a bottom-up approach, starting with individual components and working up to the system level. HAZOP starts at the system level and then drills down to individual components.
  • FMECA uses a quantitative approach to assess risk while HAZOP is primarily qualitative.
  • FMECA produces a ranked list of priorities for addressing risks while HAZOP does not.
  • FMECA can be used throughout the life cycle of a system while HAZOP is typically used during design reviews.


In conclusion, FMECA is a powerful tool that can be used to quickly assess potential failure and effectiveness of components and systems. By applying this technique, organizations can identify critical system deficiencies before they have an impact on operations. Understanding its principles, utilizing its various types of data inputs, and educating yourself on the correlations between risk level categories help make the most of the power of FMECAs Criticality Matrix for diagnostic purposes.

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