Introduction

Emergency System Survivability Assessment (ESSA) is a structured analysis used to evaluate whether critical safety and emergency systems can continue to function during major accident events such as fire, explosion, or gas release. In high-hazard facilities, these systems – ranging from fire and gas detection to emergency shutdown, power supply, and communication – are essential to protect personnel and control escalation. ESSA provides a performance-based evaluation of how these systems behave under extreme conditions, ensuring that they remain available for the duration required to support safe evacuation and emergency response.

Purpose

• Assess the survivability of critical emergency and safety systems during accident scenarios
• Identify vulnerabilities to heat, overpressure, smoke, and toxic exposure
• Verify that systems remain operational for the required time to support evacuation and response
• Evaluate routing, redundancy, and protection of cables, equipment, and control systems
• Support compliance with safety case requirements and industry standards
• Strengthen overall barrier management and emergency preparedness

Outcomes

• Identification of critical system vulnerabilities under fire and explosion conditions
• Assessment of survivability duration for key safety and emergency systems
• Verification of system integrity and availability during emergencies
• Recommendations for mitigation measures (e.g., fireproofing, rerouting, redundancy)
• Improved reliability of emergency response systems
• Integration with EERA, FERA, and Safety Critical Element (SCE) frameworks