System Design Description (SyDD) — ISO/IEC/IEEE 15289 — Description | IEEE 29148 §6.5
Generated 2026-03-27 — UHT Journal / universalhex.org
flowchart TB n0["system<br>Offshore Oil Platform Safety System"] n1["subsystem<br>Fire and Gas Detection System"] n2["subsystem<br>Emergency Shutdown System"] n3["subsystem<br>Process Safety System"] n4["subsystem<br>Fire Protection System"] n5["subsystem<br>Blowout Prevention System"] n6["subsystem<br>HVAC Safety System"] n7["subsystem<br>Public Address and General Alarm System"] n8["subsystem<br>Emergency Evacuation System"] n1 -->|Confirmed Hazard Alarms| n2 n1 -->|Fire Confirmed Signal| n4 n2 -->|Process Shutdown Trigger| n3 n2 -->|HVAC Isolation Commands| n6 n2 -->|Well Shutdown Command| n5 n2 -->|Alarm Activation Signal| n7 n7 -->|Muster and Abandon Commands| n8 n3 -->|Trip Escalation| n2
Offshore Oil Platform Safety System — Decomposition
| Entity | Hex Code | Description |
|---|---|---|
| Blowout Prevention System | DFF73859 | Well control safety system for an offshore oil production platform comprising subsea BOP stack (annular preventer, pipe rams, blind/shear rams), surface BOP controls, hydraulic accumulator unit (koomey unit), choke and kill manifold, and emergency disconnect system (EDS). Provides last line of defence against uncontrolled hydrocarbon release from the wellbore. Accumulator system must maintain sufficient stored energy to close all BOP functions plus one annular with no external power. Shear rams capable of cutting drill pipe and sealing the wellbore within 45 seconds. Interfaces with ESD system for automatic BOP closure on platform ESD Level 1. Compliant with API 53 and regional well control regulations. |
| Emergency Evacuation System | 50FD7A59 | Personnel evacuation and escape system for an offshore oil production platform comprising TEMPSC (totally enclosed motor propelled survival craft) with davit launch systems, secondary evacuation means (marine escape chutes, scramble nets, life rafts), escape route lighting (battery-backed photoluminescent and LED), muster area monitoring (electronic mustering via personnel-on-board tracking), and helicopter evacuation coordination. TEMPSC launch system must achieve full deployment within 10 minutes. Escape routes designed for maximum 800mm bottleneck with illumination maintained for minimum 3 hours post-power loss. Electronic mustering system tracks all personnel and provides real-time headcount to OIM (Offshore Installation Manager). Interfaces with PA/GA for muster and abandon commands. |
| Emergency Shutdown System | 51F77A59 | Safety Instrumented System implementing IEC 61511 SIL 3 safety functions for an offshore oil production platform. Executes hierarchical shutdown sequences (ESD Level 1: total platform shutdown; ESD Level 2: area isolation; ESD Level 3: unit/equipment isolation) based on confirmed hazard inputs from Fire and Gas Detection and process trip signals. Uses Triple Modular Redundant (TMR) logic solvers with <100ms scan time. Drives ESD valves (fail-safe-close), ignition source isolation, HVAC damper closure, and process depressurisation. Cause-and-effect matrix defines all input-output relationships. Must achieve <1 second from confirmed input to final element actuation for Level 1 shutdown. |
| Fire and Gas Detection System | 55F77A19 | Distributed network of hydrocarbon gas detectors (catalytic bead, infrared point, and open-path), flame detectors (UV/IR multi-spectrum), heat detectors (rate-of-rise and fixed-temperature), and smoke detectors deployed across an offshore oil production platform. Provides 2ooN voting logic per zone to minimise spurious trips while maintaining SIL 2 detection integrity. Covers process areas, wellhead deck, turret, and accommodation module. Outputs confirmed alarm signals to the Emergency Shutdown System within 3 seconds of hazard confirmation. Interfaces with F&G logic solver (typically TMR architecture) and diagnostic system for detector health monitoring. |
| Fire Protection System | 55F73A58 | Active fire suppression system for an offshore oil production platform comprising deluge water spray (process areas, wellhead), foam concentrate injection (helideck, storage tanks), CO2 flooding (enclosed electrical rooms, turbine enclosures), and dry chemical powder (small hazard areas). Firewater ring main pressurised by diesel-driven and electric firewater pumps with dedicated seawater intake. Deluge valve activation triggered by Fire and Gas Detection confirmed alarm or manual call points. Delivers minimum 10 L/min/m2 water application rate over protected areas. Includes passive fire protection monitoring (PFP integrity sensors on structural steel and vessel supports). Total firewater demand calculated per area-based worst-case fire scenario. |
| HVAC Safety System | 51F77A59 | Heating, ventilation, and air conditioning isolation and control system for emergency conditions on an offshore oil production platform. On confirmed gas detection or ESD activation, closes HVAC supply and return dampers to affected zones within 5 seconds, isolates air handling units, and activates pressurisation of safe refuge (temporary refuge/TR) to maintain positive pressure differential of minimum 50 Pa. Prevents migration of flammable or toxic gas into accommodation, control room, and electrical equipment rooms. Zone-based damper control linked to F&G detector zones via the ESD system. Includes smoke extraction for accommodation areas. Battery-backed damper actuators ensure fail-safe-close on power loss. |
| Offshore Oil Platform Safety System | 51F77A59 | Integrated safety instrumented system for an offshore oil and gas production platform (FPSO or fixed jacket). Comprises fire and gas detection, emergency shutdown (ESD), process shutdown (PSD), blowout prevention, fire suppression (deluge, foam, inert gas), HVAC isolation, emergency evacuation and escape systems, and safety-critical communications. Operates in harsh marine environment (North Sea or Gulf of Mexico class). Designed to IEC 61511 / IEC 61508 with SIL 2/3 safety functions. Interfaces with the process control system (DCS), platform management system, and shore-based emergency coordination centre. Must achieve <1s response time for ESD activation from confirmed hazard detection. Handles hydrocarbon release, fire, toxic gas, structural failure, and man-overboard scenarios. |
| Process Safety System | 55F77A59 | Safety Instrumented System providing SIL 1/2 safety instrumented functions for process parameter protection on an offshore oil production platform. Monitors process variables (pressure, temperature, level, flow) via dedicated safety transmitters and executes trip actions (close safety valves, activate pressure relief, stop pumps/compressors) when setpoints are exceeded. Separate from and independent of the Emergency Shutdown System — PSS handles process upsets before they escalate to ESD-level events. Uses 1oo2 or 2oo3 voting architectures depending on SIL level. Approximately 40-60 safety instrumented functions per platform. Proof test intervals typically 12-24 months. |
| Public Address and General Alarm System | 54FD7A18 | Integrated alarm and communication system for an offshore oil production platform providing audible and visual emergency notifications across all platform areas including open decks, process areas, accommodation, and helideck. General alarm activated automatically by ESD system or manually from control room and local alarm stations. Minimum 65 dBA above ambient noise in all areas (typically 110+ dBA in process areas). PA system provides intelligible voice announcements with Speech Transmission Index (STI) >= 0.5. Visual alarm beacons (xenon or LED) in high-noise areas. Interfaces with emergency response coordination for evacuation commands. Powered by dedicated UPS with minimum 30-minute battery backup. Zone-based alarm activation allows area-specific alerts. |
| Component | Belongs To |
|---|---|
| Fire and Gas Detection System | Offshore Oil Platform Safety System |
| Emergency Shutdown System | Offshore Oil Platform Safety System |
| Process Safety System | Offshore Oil Platform Safety System |
| Fire Protection System | Offshore Oil Platform Safety System |
| Blowout Prevention System | Offshore Oil Platform Safety System |
| HVAC Safety System | Offshore Oil Platform Safety System |
| Public Address and General Alarm System | Offshore Oil Platform Safety System |
| Emergency Evacuation System | Offshore Oil Platform Safety System |