title: Safety Systems Documentation description: Navigation for NeqSim process-safety, relief, ESD, HIPPS, risk, consequence, and barrier-analysis guides. keywords: “safety, SIS, ESD, HIPPS, blowdown, depressurization, relief valve, PSV, API 520, API 521, fire case, source term, consequence, HAZOP, LOPA, alarm, trip” —
Use this hub to choose the safety-analysis layer that matches the engineering question. The process-safety API overview explains current equipment, logic, scenario-runner, units, and lifecycle boundaries. The guides below provide focused workflows and screening methods.
NeqSim results are engineering evidence, not approval. Project-specific hazards, design conditions, standards editions, safeguard independence, uncertainty, acceptance criteria, and accountable review remain mandatory.
Start here
| Need | Guide |
|---|---|
| Choose equipment, logic, or scenario APIs | Process-safety API overview |
| Size or screen relief devices | Relief-Valve Sizing Screening |
| Test ESD logic dynamically | ESD dynamic testing workflow |
| Model HIPPS voting and action | HIPPS implementation |
| Generate safety scenarios | Safety scenario generation |
| Review releases and consequence inputs | Release and dispersion scenarios |
| Trace barriers and safety-critical elements | Barrier management and SCE traceability |
Emergency shutdown and blowdown
| Document | Description |
|---|---|
| ESD dynamic testing workflow | Dynamic ESD testing with process logic, OperationalTagMap/tagreader evidence, and JSON criteria reports |
| ESD and blowdown system | Complete ESD and blowdown-system guide |
| Pressure monitoring for ESD | Pressure monitoring and shutdown logic |
| API 521 depressurization workflow | Dynamic depressurization screening and API 521 interpretation boundary |
| Integrated safety systems | Integrated shutdown, isolation, blowdown, and relief overview |
HIPPS and safety-instrumented functions
| Document | Description |
|---|---|
| HIPPS overview | HIPPS concepts, voting, and implementation map |
| HIPPS implementation | Detector, voting, logic, and final-action workflow |
| HIPPS safety logic | Safety-logic programming and state behavior |
| SIS logic implementation | Safety-instrumented-system logic |
| NOG 070 SIL, STS-0131 gate, and ESD response time | Predetermined SIL, acceptance gate, and response-time budget |
| Safety-chain integration tests | Integrated safety-chain verification |
Hazard identification, risk, and barriers
| Document | Description |
|---|---|
| HAZOP guide | Hazard-and-operability study structure and guidewords |
| Automated HAZOP from STID and simulation | STID/P&ID, plant data, simulation, HAZOP, barrier, and report workflow |
| AI-HAZOP input-data format | Required process, deviation, design-condition, and limit-basis inputs |
| FMEA guide | Failure-mode and effects analysis workflow |
| Event and fault trees | Event-tree and fault-tree modeling |
| Layered safety architecture | Defense-in-depth and protection-layer structure |
| Barrier management and SCE traceability | Evidence-linked PSFs, SCEs, performance standards, and analysis handoffs |
| ISO 17776 MAH bow-tie and EI AVIFF FIV screening | Major-accident-hazard bow-tie and flow-induced-vibration screening |
| Safety simulation roadmap | Maintained capability and development roadmap |
Standards and facility screening
| Document | Description |
|---|---|
| API RP 14C SAFE chart and NORSOK P-002 compliance | SAFE chart, flare/blowdown/vent screening, and multi-vessel header load |
| Flare flame, hazardous area, and PFP demand | API 537, IEC 60079-10-1, and API 521 screening |
| Open-drain review with NeqSim evidence | NORSOK S-001 open-drain review using calculated leak and firewater loads |
| Minimum design metal temperature assessment | MDMT evidence and low-temperature screening |
Relief systems and trapped inventory
| Document | Description |
|---|---|
| Relief-Valve Sizing Screening | Static gas, liquid, two-phase, and wetted-fire sizing APIs with explicit SI units |
| PSV dynamic sizing example | Pressure-safety-valve dynamic sizing workflow |
| Rupture-disk dynamic behavior | Burst, opening, flow, and reset-state behavior |
| Trapped inventory calculator | Evidence-linked isolation inventory for blowdown, flare-load, and MDMT screening |
| Blocked-in liquid thermal expansion | Isochoric pressure-rise and thermal-relief screening |
| Trapped liquid fire rupture | Fire exposure, expansion, failure screening, PFP demand, and source-term handoff |
| Vessel thermomechanical safety | Blowdown, filling, boil-off, composite-wall conduction, and rupture models |
Fire, release, and consequence
| Document | Description |
|---|---|
| Fire-case blowdown capabilities | Fire-exposed blowdown simulation |
| Fire heat-transfer enhancements | Fire heat flux and wall heat-transfer modeling |
| Dispersion and consequence | Source-term, dispersion, radiation, and consequence-analysis handoff |
| Release and dispersion scenarios | Structured release scenarios with explicit inputs and limitations |
| Vessel thermomechanical safety | Dynamic PSV screening and thermomechanical response |
| Trapped liquid fire rupture | Blocked-in liquid fire and rupture screening |
Alarms and architecture
| Document | Description |
|---|---|
| Alarm-system guide | Alarm configuration and behavior |
| Alarm-triggered logic examples | Alarm-driven process logic |
| Integrated safety systems | Facility safety-system overview |
| Layered safety architecture | Independent protection layers and defense in depth |