Because it simplified the math, the results were often too conservative or not precise enough for high-stakes industrial sites. Phase-Out:
of potential failures. On the screen, a heat map blossomed. It wasn't the sea of green Elias had hoped for. A pulsing amber zone appeared near the main transformer line—a Risk Priority Number (RPN) that exceeded their old manual estimates.
"It’s just a calculator," Henderson argued. "It’s a simplified tool. It doesn't know the real world."
| Hazard | S | F | P | Pr | Risk Class | Required SIL | |--------|---|---|---|----|------------|----------------| | Rotating shaft access | 2 | 2 | 2 | Medium | 4 | SIL 2 | | Chemical spray | 1 | 1 | 1 | Low | 1 | No safety function needed | | Unexpected startup | 2 | 2 | 2 | High | 5 | SIL 3 |
Why should the average engineer care about the ? Because the law (EU Machinery Directive 2006/42/EC, UK PUWER 98, US OSHA General Duty Clause) requires a documented risk assessment.