FMEA – Probability of Detection

Probability of detecting a failure if it has occurred.

The definition varies for different types of FMEA analysis. Therefore, it is necessary to specify the type of analytical process (for individual failures or for properties).

The following overview is based on the automotive industry standard. Before using, check whether it is relevant for your case!

DFMEA

Level 1: It is known that the design cannot fail
Level 2: Verified standard procedures, aging control
Level 3: Verified standard procedures, failure test
Level 4: Verified standard procedures, function pass test
Level 5: Verified standard procedures in the late development phase, aging control
Level 6: Verified standard procedures in the late development phase, failure test
Level 7: Verified standard procedures in the late development phase, low, function pass test
Level 8: New test procedures are used, which are not verified
Level 9: Known tests are not specifically designed to verify potential failures
Level 10: Test procedures have not yet been developed

PFMEA

Level 1: Failure is virtually impossible or cannot go undetected
Level 2: Proven reliable detection methods; machine inspections prevent the occurrence of defective products
Level 3: Proven detection methods; defective products are automatically detected
Level 4: Proven detection methods; reliable inspections detect the problem during production and reject defective products
Level 5: Verified inspections; semi-automatic detection alerts the operator
Level 6: Verified inspections; manual inspection of products or samples detects defects
Level 7: Unverified inspections; semi-automatic detection alerts the operator
Level 8: Unverified inspections depend on manual inspection of products or samples to detect defects
Level 9: It is unlikely that inspections will detect the problem; sample checks may not easily identify the issue
Level 10: It is unlikely or impossible to detect the issue through inspections

FMEA-MSR

Level 1: Always detected – significantly more than 99.9%; the system responds to failures
Level 2: Detected with probability > 99.9%, the system is very likely to identify the failure
Level 3: Automatic detection identifies failures with probability > 99% with a short response time, automatic reaction is highly probable
Level 4: Detection with probability > 97% with medium response variability; the system will usually react to failures
Level 5: Detection with probability 90–97%, with moderate response variability; the system will usually respond automatically to failures
Level 6: The failure is detected by the user or system with probability > 90% and will likely be able to respond
Level 7: Low probability that the us

Useful links to sites

• FMEA Severity Rating
• FMEA Occurrence Rating
• About FMEA in general