For an FMEA with a severity of 9, occurrence of 2, and detection of 1, what is the risk priority number (RPN)?

• A. 4
• B. 6
• C. 12
• D. 18

Answer: (D)

To determine the Risk Priority Number (RPN) for the given Failure Modes and Effects Analysis (FMEA) scenario, you multiply the severity, occurrence, and detection ratings together. The formula for calculating the RPN is:

RPN = Severity × Occurrence × Detection

In this case, the severity is 9, the occurrence is 2, and the detection is 1. When you perform the calculation:

RPN = 9 × 2 × 1 = 18

This result signifies a higher risk priority, indicating that the failure modes represented by these ratings should be addressed with significant priority due to their potential severity and likelihood of occurrence. An RPN of 18 suggests that while detection is low (indicating that the failure may go unnoticed), the severity of the potential failure is critical, warranting substantial attention to mitigate risks associated with it.

This understanding underlines the importance of each component in the RPN calculation, illustrating how different aspects of risk (severity, occurrence, and detection) combine to inform decision-making in quality management processes.