CONTENTS

A.1.     INTRODUCTION................................................................................................... 3

A.2.     DEFINITIONS....................................................................................................... 4

A.3.     INCIDENT LIKELIHOOD........................................................................................... 4

A.4.     Consequence Severity  and Risk Assessment................................................................... 18

A.5.     Guideline for Safety Consequence Severity Assessment....................................................... 24

A.5.1.     Overpressure Scenarios.................................................................................... 25

A.5.2.     Overtemperature Scenarios............................................................................... 27

 

. INTRODUCTION

The Hazard Assessment procedure is based on the principles of 'identify', 'assess', 'control' and 'mitigate', with the individual stages summarized in the following steps:

• Identify Hazards and Potential Effects;
• Evaluate Hazards / Risks;
• Compare with Objectives and Performance Criteria;
• Establish Hazard / Risk Reduction Measures.

A risk matrix is used hazard/for risk evaluation by combining the likelihood category and the consequence severity rating.

Layer of Protection Analysis (LOPA) is a semi-quantitative risk analysis technique to assess the risk level of an undesired consequence, usually an event with health, safety, environmental or economic impact.

The concept behind the LOPA analysis is shown in the following Figure A.1. Several safeguards, of different type, are been foreseen to prevent, control or mitigate unwanted outcome of process deviation, from the design of the process itself up to the plant emergency response, if needed