FMEA / FMECA Worksheet (IEC 60812)
neqsim.process.safety.hazid.FMEAWorksheet provides a Failure Modes, Effects
and Criticality Analysis worksheet aligned with IEC 60812 (2018). Each entry
captures the failure mode of a tagged component and its three risk dimensions.
Risk Priority Number
\[\mathrm{RPN} = S \cdot O \cdot D\]where each factor is on a 1–10 scale:
- S (Severity) — consequence severity if the mode occurs
- O (Occurrence) — likelihood of the mode
- D (Detection) — inverse detectability (10 = undetectable)
Code pattern
FMEAWorksheet fm = new FMEAWorksheet("Subsea Tree — XT-001");
fm.addEntry("PT-101", "Transmitter", "Drift high",
"Sensor degradation",
"Spurious ESD trip, lost production",
4, 5, 3); // S, O, D — RPN = 60
fm.addEntry("BDV-202", "Blowdown valve", "Fail to open",
"Solenoid coil failure",
"Cannot depressurize during fire — vessel rupture risk",
9, 2, 6); // RPN = 108
List<FMEAWorksheet.Entry> hotList = fm.criticalEntries(100); // RPN > 100
Common thresholds
| Threshold | Action |
|---|---|
| RPN > 200 | Mandatory mitigation — design change |
| RPN 100–200 | Mitigation recommended — added safeguard or inspection |
| RPN < 100 | Monitor in operating phase |