Emergency Systems Survivability Assessment (ESSA) Study

What is Emergency Systems Survivability Assessment (ESSA) ?

Emergency Systems Survivability Assessment (ESSA) is a critical evaluation process designed to ensure the resilience and effectiveness of emergency response systems in various industries, particularly in high-risk sectors such as oil and gas, chemical manufacturing, and power generation. The primary goal of ESSA is to assess how well emergency systems can withstand and function during adverse events, including natural disasters, equipment failures, and other crises.

When to perform ESSA ?

The ESSA is an integral part of the risk management process to ensure that the risk is managed at tolerable levels and ALARP demonstrated for both project activities and operations. Typically, Comprehensive ESSA is performed during the FEED Stage of the project and is later updated during the EPC (Detailed Engineering) Stage based on newly established information/data/engineering documentations etc.

How it is performed?

The survivability of each selected emergency systems is checked against three factors:.

• • Vulnerability - whether an emergency system can be impaired/damaged by the identified major accident and if so, whether it can survive long enough during the major accident and perform its intended function successfully
• • Fail-safe - when impaired, whether an emergency system will perform its intended function or not
• • Redundancy - whether there are auxiliary systems available to replace the main system if it is impaired

TIf an emergency system is found not to be vulnerable to a major accident or if it is vulnerable but fails safe or has redundancy, it is deemed to be able to survive and capable of achieving its safety function. Otherwise, recommendations/action plans shall be proposed in order to improve its survivability.

In order for ESSA to be effective, Project Fire and Explosion Risk Assessment (FERA) study shall assess each and every Safety Critical Element (SCE) for the adopted hazard end points in project.