Understanding the Risk Priority Number (RPN)

The **Risk Priority Number (RPN)** is a key metric used in **Failure Modes and Effects Analysis (FMEA)** to assess and prioritize risks in a system, product, or process. It helps organizations **identify critical failure points** and take action before they lead to significant issues.

Why Do We Use RPN?

• To **quantify risks** and prioritize them based on severity.
• To **identify potential failure modes** that could impact operations, products, or safety.
• To **improve decision-making** by highlighting high-risk areas that require immediate attention.
• To **reduce failures and enhance safety** by mitigating risks before they escalate.

Understanding Each Factor

1. Probability (1-10) – How Likely is the Failure?

**Definition:** Probability measures how likely a failure mode is to occur. A higher value means the failure is **more probable**. **Why It Matters:** If a failure is highly probable, it requires **proactive measures** to prevent it.

• **1 (Very Low):** Almost no chance of occurrence.
• **5 (Moderate):** Could happen occasionally.
• **10 (Very High):** Almost certain to happen.

2. Occurrence (1-10) – How Frequently Does It Happen?

**Definition:** Occurrence measures how often a failure mode has been observed in practice. **Why It Matters:** Frequent failures indicate **system weaknesses** that need attention.

• **1 (Very Rare):** Happens once in a long period.
• **5 (Moderate):** Happens a few times a year.
• **10 (Frequent):** Happens regularly or daily.

3. Detection (1-10) – How Easily Can We Detect It?

**Definition:** Detection measures the **ability to identify a failure before it causes damage**. **Why It Matters:** A low detection score means the failure might go unnoticed until it causes a major problem.

• **1 (Very High Detection):** Failure is very easy to detect.
• **5 (Moderate Detection):** Somewhat difficult to detect.
• **10 (Very Low Detection):** Almost impossible to detect before it happens.

How to Use This Calculator

Enter values for **Probability, Occurrence, and Detection** (each between 1 and 10). The calculator will compute the **Risk Priority Number (RPN)**. Higher RPN values indicate **greater risk**, meaning action is needed.