Emergency Systems Survivability Analysis

Emergency systems are those systems that are essential for the preservation of human life and the maintenance of life support after a major accident event on an installation.  Emergency Systems Survivability Analysis (ESSA) is intended to assess the ability of emergency systems to withstand accident conditions such as fire, smoke, toxic gas, and blast.
Emergency Systems Survivability Assessment (ESSA) is a technique to assess the survivability of the emergency system to perform its design intent during major accident events, such as fire, smoke, blasts, and hazardous gas releases.
The main purpose of the Emergency Systems Survivability Assessment is to analyse those systems that are necessary for the protection of human life following any main accidental event, and to maintain life support on the installation.
ESSA systematically evaluates the ability of the identified emergency systems to operate as intended during emergency conditions, including fire, toxic gas release, explosion, etc. Findings of quantitative risk assessment and other safety studies, to be performed as part of the existing project scope, can be utilized in the assessment.
An Emergency Systems Survivability Assessment examines the vulnerability of key emergency systems to demonstrate that they can perform their safety function under the conditions in which they are required.  It is applied to many emergency systems on an installation, typically including:
⦁ Fire and gas detection and alarm systems.
⦁ Emergency shutdown and blowdown systems.
⦁ Fire-fighting systems (e.g., fire water, foam, etc.).
⦁ Passive fire protection.
⦁ Ventilation system.
⦁ Emergency power and communication systems.
⦁ Escape routes, mustering arrangement and command system.
⦁ Personal survival equipment (e.g., life jackets, smoke hood, etc.)
⦁ Evacuation system (e.g., lifeboats, life rafts, etc.).
The objective of the ESSA is to identify those systems that are essential for the preservation of human life following any major accidental event and necessary to maintain life support on the installation.
Methodology
ESSA shall systematically assess the capability of the identified emergency systems to operate as intended during emergency conditions, i.e., fire, toxic gas release, explosion, etc.  Findings of QRA and other safety studies, to be carried out as part of the present project scope, shall be utilized in the assessment.
The ESSA shall consider the following systems, as minimum, as part of present scope:
⦁ Emergency Shutdown Systems
⦁ Emergency depressurisation systems
⦁ Fire and gas detection systems
⦁ Platform Alarms
⦁ Active Fire protection systems and Equipment
⦁ Vent Fire Snuffing Equipment
⦁ Passive Fire Protection System
⦁ Egress to sea and Life Saving Appliances (LSAs)
⦁ UPS and Emergency power
⦁ NavAids and Communication
⦁ Signs and lighting
The ESSA shall aim to demonstrate that the emergency systems identified above will function following all identified major accidental events, and that all reasonable design features have been incorporated to meet this need as far as is practicable.  The vulnerability and survivability of the identified systems following an accident event shall also be assessed.
The overall approach to the ESSA is summarised as follows:
⦁ Develop a definition for Safety Critical (i.e., emergency) systems
⦁ Identify all Major Accident Hazard (MAH) events and their ability to impair the identified safety systems required during an emergency
⦁ Identify all emergency systems (according to the above definition of safety criticality) presently in operation on the platform, their function, constituent parts and locations
⦁ For each MAH, determine which emergency systems are required for prevention of that accident and which systems are required to prevent escalation
⦁ Determine the vulnerability of each of the emergency systems in the accident events they are designed to mitigate
⦁ Determine the redundancy or duplication of emergency system components or alternative systems
⦁ Complete the emergency systems assessment in the light of the above analysis