The fourth step in the standard FMEA process is assigning a Detection Rating.


Introduction to the fourth step of FMEA

  • Severity Rating: Assesses the seriousness of the effect of a potential failure mode.
  • Occurrence Rating: Estimates the likelihood or frequency of the failure mode happening.
  • Effects of the Failure: Each failure mode is evaluated for its potential impact or consequences on the system or the end user.
  • Detection Rating: This assesses the probability that the failure mode will be detected or identified before it reaches the end user or causes a more significant system issue. It gauges how well current controls (like testing, monitoring, or quality checks) can discover or prevent the failure.

Typically, the detection rating is scored on a scale, often from 1 to 10, where a lower score indicates a high likelihood of detection and a higher score suggests that the failure mode is less likely to be detected before causing an issue.

The Detection Rating in FMEA evaluates the effectiveness of the current controls (tests, procedures, mechanisms) in detecting or identifying a failure mode before it reaches the customer or causes subsequent failures in the system. Essentially, it’s an assessment of your preventive measures and their robustness.

Key Aspects of the Detection Rating:

  • Nature of Controls: The Detection Rating looks at the types of controls currently in place. This could be automatic detection mechanisms, manual inspections, audits, or any other method used to catch failures.
  • Efficiency of Controls: Not all controls are 100% effective. The rating assesses how reliably these controls can catch or prevent the identified failure mode. For instance, if a particular defect is caught only half the time during inspections, then the detection capability is not very strong.
  • Rating Scale: The scale typically runs from 1 to 10. A rating of 1 would mean that there’s an excellent chance that the existing controls will detect the failure mode, while a rating of 10 implies that it’s highly unlikely the failure will be detected before it reaches the end user or causes further complications.
  • Position of Control: Controls that are closer to the source of potential failure and those that are more direct are generally deemed more effective. For instance, an in-process inspection might be considered more effective than a final inspection because errors can be detected and corrected immediately.
  • Feedback Loops: An effective detection mechanism often has feedback loops that allow for continuous improvement. If a control mechanism can provide insights that lead to process improvements, it might be deemed more effective.
  • Implications of Non-Detection: In assigning a Detection Rating, it’s also valuable to consider the implications of a failure going undetected. Some failures, even if they have a low occurrence rate, might have catastrophic consequences if not detected.
  • Updating Detection Ratings: As new data is acquired, controls are enhanced, or as processes change, the Detection Rating for a particular failure mode might need revisiting and updating.

To put it into perspective, imagine you’re manufacturing car brakes. One potential failure mode might be that the brake pads are not aligned correctly. The effect is that the car might not stop effectively, which would have a high severity rating. If historical data shows this happens once in every 500 units, it would get a particular occurrence rating. Now, if there’s an automated scanning system in place that checks the alignment of every brake pad and has a proven track record of catching misalignments, then the detection rating would be quite low, indicating a high level of confidence in the control.

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FAQ: Pressure Vessel Manufacturing and FMEA Process

What is Failure Mode and Effects Analysis (FMEA) in the context of pressure vessel manufacturing?

Failure Mode and Effects Analysis (FMEA) is a systematic, proactive method for evaluating a process to identify where and how it might fail and to assess the relative impact of different failures. In pressure vessel manufacturing, FMEA is crucial for identifying potential failure modes in the design and manufacturing process, analyzing their effects on the vessel’s performance and safety, and implementing strategies to mitigate these risks.

How does FMEA contribute to the safety and reliability of pressure vessels?

FMEA enhances the safety and reliability of pressure vessels by methodically analyzing potential failure points in their design, fabrication, and operational stages. By anticipating and addressing these failure modes, manufacturers can implement design modifications, choose appropriate materials, and establish quality control measures that significantly reduce the likelihood of failures, thereby ensuring the vessel’s integrity and operational safety.

What is the fourth step in the FMEA process, and why is it important?

The fourth step in the FMEA process is ‘Risk Prioritization’. After identifying potential failure modes, their effects, and causes, this step involves evaluating the severity, occurrence, and detection of each failure mode to prioritize them based on risk. This prioritization helps in focusing on the most critical issues first, ensuring that resources are allocated effectively to mitigate the highest risks to the pressure vessel’s safety and functionality.

Can FMEA in pressure vessel manufacturing help in compliance with industry standards?

Absolutely. FMEA is a valuable tool in ensuring compliance with industry standards such as the ASME Boiler and Pressure Vessel Code. By systematically identifying and addressing potential failure modes, manufacturers can ensure that their vessels meet or exceed these standards, which cover design, materials, fabrication, inspection, testing, and certification.

How does Red River LLC incorporate FMEA in its manufacturing process?

At Red River LLC, FMEA is an integral part of our manufacturing process. We employ it from the initial design phase through to production and testing. This approach allows us to identify potential failure modes early and implement strategies to mitigate them, ensuring the highest quality and safety standards. Our commitment to continuous improvement means that we constantly refine our FMEA processes, staying ahead of industry standards and client expectations.


In the realm of industrial solutions, Red River emerges as a pioneer, offering a diverse range of custom-engineered products and facilities. Among our specialties is the design and production of Custom/OEM Pressure Vessels, meticulously crafted to meet individual client requirements, ensuring performance under various pressure conditions. Our expertise extends to the domain of prefabrication, where Red River leads with distinction.

The company excels in creating prefabricated facilities, modules, and packages, reinforcing its stance as a forerunner in innovation and quality. This proficiency is further mirrored in their Modular Skids offering, where they provide an array of Modular Fabricated Skid Packages and Packaged equipment. Each piece is tailored to client specifications, underlining their commitment to delivering precision and excellence in every project they undertake.

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Red River is a leader in prefabricated facilities, modules and packages.

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