📋 Case Study
Confined Space Entry Protocol Optimization at Offshore LNG Terminal
Historically reliant on single gas detector and manual ventilation log; near-miss incident revealed inadequate IPL depth against asphyxiation hazard
🏗️ Project Overview
Routine entry into cryogenic liquid nitrogen storage tank for internal inspection
🎯 Challenge
Historically reliant on single gas detector and manual ventilation log; near-miss incident revealed inadequate IPL depth against asphyxiation hazard
🔧 Design Approach
LOPA-based redesign: fixed O₂ sensor with auto-alarm, forced-air ventilation interlocked to entry permit, real-time atmospheric telemetry to control room, and trained rescue team on standby (validated 10-min response)
📐 Design Diagram
AI-generated project design illustration
📐 Key Calculations
Gas Detector PFD
Manufacturer MTBF + calibration interval + drift rate
Result: 0.05
Limits IPL credit to RRF = 20 without redundancy
Ventilation Interlock RRF
1 / (PFD of control relay + valve actuator)
Result: 120
Primary IPL due to automatic enforcement
Rescue Team RRF
β × response reliability × training frequency
Result: 10
Secondary IPL contingent on documented drills
📊 Results
Asphyxiation risk reduced from 0.015/yr → 0.00012/yr; achieved ALARP; adopted as corporate standard across 12 terminals💡 Lessons Learned
- •Fixed instrumentation with interlocks provides superior IPL reliability vs portable meters
- •Rescue capability must be measured, not assumed — requires drill records, equipment readiness logs, and response time tracking
✅ Key Takeaways
- 1Fixed instrumentation with interlocks provides superior IPL reliability vs portable meters
- 2Rescue capability must be measured, not assumed — requires drill records, equipment readiness logs, and response time tracking
📐 Prerequisites
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