Plant Hazard Analysis and Safety Instrumentation Systems

Swapan Basu

• Publisher: Academic Press
• Year: 2016
• eBook ISBN: 9780128038215
• Topic: Technology & Engineering
• Subtopic: Insurance
• Index: Technology & Engineering

Plant Hazard Analysis and Safety Instrumentation Systems is the first book to combine coverage of these two integral aspects of running a chemical processing plant. It helps engineers from various disciplines learn how various analysis techniques, international standards, and instrumentation and controls provide layers of protection for basic process control systems, and how, as a result, overall system reliability, availability, dependability, and maintainability can be increased. This step-by-step guide takes readers through the development of safety instrumented systems, also including discussions on cost impact, basics of statistics, and reliability. Swapan Basu brings more than 35 years of industrial experience to this book, using practical examples to demonstrate concepts. Basu links between the SIS requirements and process hazard analysis in order to complete SIS lifecycle implementation and covers safety analysis and realization in control systems, with up-to-date descriptions of modern concepts, such as SIL, SIS, and Fault Tolerance to name a few. In addition, the book addresses security issues that are particularly important for the programmable systems in modern plants, and discusses, at length, hazardous atmospheres and their impact on electrical enclosures and the use of IS circuits. - Helps the reader identify which hazard analysis method is the most appropriate (covers ALARP, HAZOP, FMEA, LOPA) - Provides tactics on how to implement standards, such as IEC 61508/61511 and ANSI/ISA 84 - Presents information on how to conduct safety analysis and realization in control systems and safety instrumentation

Chapter I

Basics of Hazard, Risk Ranking, and Safety Systems

Abstract

There is no plant in the world which is free from any risk, but lessons learned from a disaster was realized only after the Bhopal incident, and there are a number of standards are now in effect. In order to mitigate risks, it is necessary to develop risk analysis through a risk matrix, risk ranking, and consequence calculation, which have been discussed for avoidance catastrophic consequences. For better understanding, basics of mathematics have been covered. Plant ageing, and fault tolerance issues are also important topics to be covered. Functional safety through instrumentation is a call of the day for meeting challenges for risk control. How to handle basic and control and safety in safety instrumented systems (SISs) have been covered so that required safety integrity level (SIL), demanded by various standards, have been discussed at a basic level to develop further hazard analysis and SIS.

Keywords

As low as reasonably practicable (ALARP); Basic process control systems (BPCSs); Consequence; Fault tolerance; Hazard; Plant ageing; Probability; Risk ranking; Safety instrumented function (SIF); Safety integrity level (SIL)

1.0. Introduction

This chapter gives the overall view of the entire subject in short form. This will help in understanding the subsequent details in the following chapters. Also, a few basic issues have been detailed, such as risk ranking, and risk register. So this chapter is important for following subsequent discussions.

Assets are normally acquired against a lot of efforts, toil, and monetary cost. People always wish to protect these. Unfortunately, this is not always possible on account of hazards in various forms. None desires to lose them, so people always plan to take safety measures to protect them. Until recently, in process industry, people would incorporate necessary safety measures in the form of protections under basic process control systems (BPCSs). In the arena of industrial hazard and risk analysis, “system” is defined as a subject of risk assessment, which includes mainly process, product, facility, and environmental and logical groups. So, safety associated with it needs to be treated separately from BPCS. This is more clear from subsequent discussions. Sometimes people incorporate redundancy in the system design so that in case of failure of one, there will be others available as backup, that is, to fall back. This is not true always, as is the case with common cause failure. Later, in the 1980s people tried to interface safety systems to BPCS to have better connectivity and safety controls. Initially these were based on proprietary protocol, and later people adapted open protocol systems. Although this made a better connectivity, at the same time it made the system vulnerable to external attacks such as viruses, cyber attacks, etc. After 1995, people felt the need for integration of safety systems with BPCS, without compromising functional independence between the two, to get best secured industrial systems. Therefore, people felt it was necessary to have a standard which shall be based on safety planning and safety goals based on risk assessment. As a result of this, several international standards, IEC 61508, IEC 61511, ISA 84, etc. evolved. These standards are developed mainly for electrical, electronics, and programmable electronics (E/E/PE). The primary principle behind these standards was that there is a process which may pose risk on human, machinery, asset, and environment safety, should anything goes wrong with the process, equipment, and/or operation. Naturally, these standards are aimed at process upset, or system or equipment failure, and allow the process safety to be managed in systematic way following a risk-based management system.

Again, the global financial debacle in 2008 demonstrated how important risk management is! Risk management is an increasingly important business driver, and stakeholders are extremely concerned about it. Slowly, risk management is becoming a part of strategic decision-making, and/or has been incorporated as an embedded element in routine activity. An organizational approach towards risk management enables all concerned to consider the potential impact of all types of risks on all processes...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Dedication
• Foreword
• Preface
• Acknowledgments
• Chapter I. Basics of Hazard, Risk Ranking, and Safety Systems
• Chapter II. Evaluation of Hazard and Risk Analysis
• Chapter III. Qualitative Hazard Analysis
• Chapter IV. Guided Word Hazard Analysis
• Chapter V. Quantitative Hazard Analysis
• Chapter VI. Discussions on Standards for Risk Assessment and Safety Instrumented Systems
• Chapter VII. Safety Instrumentation Functions and System (Including Fire and Gas System)
• Chapter VIII. SIL, PE, FGS, and Plant Emergencies
• Chapter IX. Safety Instrumented System Requirements for Fieldbus and Control Components
• Chapter X. Instrumentation Safety Implementation and Explosion Protection
• Chapter XI. Fault Tolerance, Protection Layer, and System Security
• Chapter XII. Discussions on the Industrial Application of SIS
• Appendix I. Popular Terms and Their Definitions
• Appendix II. Electrical Protection and Enclosure Class
• Appendix III. Simplified Mathematical Equations
• Appendix IV. Little JIL Process Language
• Appendix V. Embedded Control
• Appendix VI. Cost Impact Discussion
• Index