Failure Mode, Effects, and Criticality Analysis (FMECA)

FMECA is a great asset management practice that is used in many different industries. If you’d like to know how to use it to better your organization’s day-to-day maintenance practices, read on below.

What is FMECA?

FMECA, or failure modes, effects, and criticality analysis, is a way that organizations can identify possible failures in their system. Essentially, FMECA is failure modes and effects analysis (FMEA) with an additional focus on a criticality score, which helps organizations prioritize which issues to focus on. With this small addition to FMEA, FMECA becomes a great way for organizations to collect both quantitative and qualitative data (except for just quantitative data) with which they can assess their processes and equipment.

Ultimately, the goal of FMECA is to determine which failure modes are the riskiest for your assets so you can plan for those failures accordingly. By performing risk assessments through FMECA and using the results to plan for preventive maintenance, organizations can mitigate and prevent disasters before they occur.

You might often see the terms FMEA and FMECA used interchangeably. Nevertheless, this article will go over FMECA with the addition of criticality as an attribute for effective risk analysis and mitigation.

Who uses FMECA?

Before FMECA was developed, there was an evident need for a change in the U.S. military practice of waiting for failure to appear before handling it. Doing maintenance this way – in a reactive way – was costly, time-consuming, and unpredictable.

As a result of this need for change, FMECA grew out of U.S. military development and practice in the 1940s and is widely used in various industries even today. Examples of people who use FMECA are process engineers, design engineers, and quality engineers.

Where is FMECA used?

FMECA is frequently used by professionals in the maintenance, facilities, and manufacturing industries. It is used as a model for risk mitigation in fields such as product design, software development, and project planning.

 

Why is FMECA Important?

FMECA is a great way for organizations to get data-driven insight into their assets, allowing them to recognize potential failures in advance and plan for technical issues before they happen. Using FMECA can prevent catastrophic issues in production, design, and processes that might lead to unplanned downtime, injuries, lawsuits, or death.

Here are some situations in which you might want to use FMECA:

• You need to come up with design alternatives with high reliability and safety.
• You need to make a list of every possible failure a system could experience and its potential consequences.
• You need to assess how successful a system’s operations can be considering its potential failure modes.
• You need to create initial criteria for testing requirements.
• You need to keep detailed historical data about the system for future failure assessment.
• You want to build out a preventive maintenance schedule to mitigate failures.
• You want to collect data for reliability and availability analysis.

Types of FMECA

There are 3 types of FMECA: design, process, and system FMECA. See below for a brief description of each to help you decide which is the best type of FMECA for your situation.

• Design FMECA is done to eliminate failure during product or equipment design.
• Process FMECA is carried out to evaluate problems during equipment maintenance, manufacturing or operation.
• System FMECA focuses on potential issues with larger processes, like entire production lines.

Any of the FMECA types are useful for preemptively identifying issues with products, designs, or equipment. We suggest you select the appropriate type for the item for which you are identifying problems.

How to Perform FMECA?

FMECA is very similar to FMEA, though its process involves the addition of a criticality score. This additional attribute allows for the results of FMECA to be both quantitative and qualitative.

The steps to conducting FMECA are as follows:

Step 1: Decide on and gather information for a type of FMEA.

FMEA, which is short for failure modes and effects analysis, is the basis of FMECA. FMEA allows organizations to identify:

1. Failure modes, or how failures can occur, and
2. Effects, which are the potential consequences of said failures.

Once you’ve decided on the type of FMEA that best fits the asset, process, or design you are analyzing, take the time to gather as much information as possible about it. Use resources such as schematics, lists, and diagrams to get a better feel for the subject of your FMEA.

Step 2: Identify failure modes.

The goal here is to figure out the different ways failure could happen, and because of this, this step requires a lot of brainstorming and creativity. To help you start, think about the different ways an asset can fail. These might include:

• Unintended functionality
• Poor or insufficient functionality
• Failure to perform at all

From there, you can work backwards to figure out why these might happen. Make sure to use any historical data on whatever you are performing your analysis on to aid you with this step.

Step 3: Execute a failure effect and cause analysis.

This step involves identifying the consequences that will occur if the previously listed failure nodes happen, but it’s important to remember to also consider what might cause failures in the first place. These are the “cause and effect” parts of the failure effect and root cause analysis. For example, maybe a bearing wore out much faster than anticipated, which might be attributed to the fact that a low-quality part not recommended by the manufacturer was used.

Step 4: Assess the severity of each failure.

Severity scores are typically given on a 1-to-10 scale, with 1 being the lowest severity and 10 being the highest. See the table below for a breakdown of each score.

RATING	DEFINITION
1	None
2	Very minor severity
3	Minor severity
4-6	Moderate severity
7-8	High severity
9-10	Very high severity

When assessing severity, try to keep it in terms of the following: financial loss, safety, loss of time, equipment damage, and more. Keeping these factors in mind will help you more accurately decide on a severity score.

Step 5: Assess how often the failure occurs or is likely to happen.

This step is done much like the one above: by ranking failures on a 1-to-10 scale, with 1 being least often and 10 being most often. If you are assessing something that is already live, try to use its historical data to determine its score. If you are assessing something that isn’t being used yet, try looking at other similar assets or equipment of its type to see how often failure typically occurs.

RATING	DEFINITION
1	No failures
2-3	Low – few failures
4-6	Moderate – occasional failures
7-8	High – several failures
9-10	Very high – high probability of failures
9-10	Extremely high – total failure, hazardous to safety

Step 6: Assess how likely the failure would be to be detected.

Again, this step uses a 1-to-10 scale, with 1 being almost certain detection and 10 being a very low chance of detection. When scoring this, think about all of the control systems you have in place. Maybe you have sensors to alert you when issues come up, or maybe you do a daily inspection. Either way, include your control system in your assessment and assign a score using the chart below.

RATING	DEFINITION
1	Fault will certainly be detected
2	Fault will almost certainly be detected
3	Fault is at high probability of being detected
4-6	Fault is at moderate probability of being detected
7-8	Low probability of detecting fault
9-10	Fault will be undetected by user/customer

Step 7: Calculate the risk priority number using the scores you just gave.

The risk priority number, or RPN, is calculated by multiplying the three scores you gave in the prior steps. That makes the formula as follows:

Risk Priority Number (RPN) = Severity (S) x Occurrence (O) x Detection (D)

The formula itself results in an RPN that ranges from 1 (the best score possible) to 1000 (the worst score possible). For each possible failure, calculate the RPN and use that data to order each fault from high risk to low risk and work with your team to decide which score constitutes a critical level of risk.

Step 8: Take action.

Now that you have a list of RPNs, look for ways you can lower the RPN of each item. You can do this by making changes that alter their occurrence, detection, or severity levels.

Note that severity is often the most difficult to adjust – this is a factor that might be predetermined based on things such as the specific industry. In these cases, we suggest focusing on occurrence or detection instead, as they are much easier to improve.

Step 9: Continually recalculate RPNs.

Recalculate RPNs after changing up your processes so you can tell whether your alterations have made any sort of impact. We recommend making this an ongoing practice so you always have an eye on how well your assets, equipment, systems, or processes are doing.

How to lower RPN?

The lower the RPN of your assets, the better it’s doing. Here are a few ways you can work on lowering RPN, divided by each factor of the RPN formula:

Severity

Severity is often the most difficult item to change, as it might include drastic changes to processes, equipment, or operational costs. As such, you might want to focus on reducing either the occurrence or detection scores instead. If you are set on lowering severity, however, consider how you might eliminate the failure mode itself or its effect.

Occurrence

You can reduce occurrence by preventing or controlling its root causes. Finding and managing root causes requires a bit of brainstorming.

Detection

Detection scores can be reduced by evaluating your existing control systems. These control systems are anything used to monitor failures, such as sensors or daily inspections. Finding flaws in your detection processes and improving upon them can help you lower your detection score by leaps and bounds.

What are the benefits of FMECA?

Using FMECA offers design benefits, operations benefits, and cost benefits that might otherwise be missed. In general, FMECA helps identify critical failure mores and their effects as well as any corrective, preventive, monitoring, verification, and test data, all of which are useful for managing assets and prolonging their lives.

• Increased reliability and quality. FMECA leads to fewer failures, which leads to better-quality products and equipment that will better withstand the test of time.
• Safer products for everyone. FMECA allows you to identify and mitigate risks that might impact health and safety.
• Decreased development and redesign time. Thorough FMECA practices translate to better-performing products that don’t have to spend a lot of time in development or redesign.
• Optimized preventive and predictive maintenance. Formulate a better, more efficient PM or PdM schedule using the results you get from FMECA.
• More effective control plans and improved verification and validation testing requirements. Get a better handle on your product or equipment.
• Early failure mode identification. Catch issues before they’re too costly to address.
• Decreased warranty costs. Better performance leads to decreased warranty costs.
• Increased sales. Keep customers happy with FMECA and increase the number of sales you make.

What are the disadvantages of FMECA?

There are a few reasons why you might not want to use FMECA, including the list below.

• FMECA can be time-consuming and costly. The process of identifying and assessing failure modes could take a relatively large amount of time and resources.
• FMECA might not be suitable for all situations. Be sure to assess whether FMECA is the best way to identify and manage possible failures, and if not, consider a different approach.
• FMECA might not be accurate enough for all situations. If your project is critical and can lead to serious repercussions, make doubly sure that FMECA is the appropriate method of risk assessment.

FMECA vs FMEA

Both FMEA and FMECA are approaches used in the manufacturing process, and the main distinction between the two is that one is an extension of the other. Failure Mode and Effects Analysis (FMEA) and Failure Modes, Effects, and Criticality Analysis (FMECA) are two techniques used in identifying specific failures or errors within a product or process and taking corrective actions to rectify the problems; FMECA is a development to FMEA.

Some of the differences between FMECA and FMEA:

• The FMEA simply offers qualitative information, but the FMECA provides both qualitative and quantitative information, allowing for measurement by assigning a level of criticality to failure modes.
• FMECA is a subset of FMEA. As a result, to undertake FMECA, FMEA must be followed by critical analysis.
• FMEA evaluates the failure modes and impacts of a product or process, whereas Criticality Analysis ranks those failure modes in order of priority based on the failure rate.

Final thoughts

FMECA is a great way for organizations to practice risk mitigation, improve asset performance, and keep systems in great shape for as long as possible. We highly recommend using a CMMS to provide you with the documentation and historical data needed to make the most out of the FMECA process. If you’re interested in seeing how NEXGEN asset management solution can help you conduct FMECA, click the button below to see NEXGEN in action.