Guidelines for Inherently Safer Chemical Processes

A Life Cycle Approach

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• Publisher: Wiley-AIChE
• Year: 2019
• Print ISBN: 9781119529163
• eBook ISBN: 9781119529224
• Edition: 3
• Topic: Technik & Maschinenbau
• Subtopic: Gesundheit & Sicherheit in der Industrie

Since the publication of the second edition several United States jurisdictions have mandated consideration of inherently safer design for certain facilities. Notable examples are the inherently safer technology (IST) review requirement in the New Jersey Toxic Chemical Prevention Act (TCPA), and the Inherently Safer Systems Analysis (ISSA) required by the Contra Costa County (California) Industrial Safety Ordinance. More recently, similar requirements have been proposed at the U.S. Federal level in the pending EPA Risk Management Plan (RMP) revisions. Since the concept of inherently safer design applies globally, with its origins in the United Kingdom, the book will apply globally.

The new edition builds on the same philosophy as the first two editions, but further clarifies the concept with recent research, practitioner observations, added examples and industry methods, and discussions of security and regulatory issues. Inherently Safer Chemical Processes presents a holistic approach to making the development, manufacture, and use of chemicals safer. The main goal of this book is to help guide the future state of chemical process evolution by illustrating and emphasizing the merits of integrating inherently safer design process-related research, development, and design into a comprehensive process that balances safety, capital, and environmental concerns throughout the life cycle of the process.

It discusses strategies of how to: substitute more benign chemicals at the development stage, minimize risk in the transportation of chemicals, use safer processing methods at the manufacturing stage, and decommission a manufacturing plant so that what is left behind does not endanger the public or environment.

1
Introduction

1.1 OBJECTIVES, INTENDED AUDIENCE, AND SCOPE OF THIS BOOK

1.1.1 Objectives

The primary objective of this book is to provide a tool that can be used by any industrial company that handles hazardous chemicals to better understand inherent safety concepts and provide guidelines on how to implement them. The goal of this book is to provide practical guidelines for illustrating and emphasizing the merits of integrating research, development, and design into a comprehensive approach that balances safety, capital, and environmental concerns throughout the life cycle of the process. The authors hope that this book will help influence the next generation of engineers, chemists, and current practitioners and managers in the field of chemical processing.

Inherent safety is a powerful and effective means of reducing hazards and risk, versus managing risk by adding layers of protection. A hazard eliminated is one that then doesn't need to be addressed, which may have many direct and indirect benefits. Responsible companies understand the concept and apply it wherever and whenever it may be useful throughout the life cycle of the process. Companies who have an internal motivation to apply inherent safety routinely to the fullest capacity “as a way of doing business” recognize that doing so is beneficial.

In 1996, the Center for Chemical Process Safety (CCPS) published the first edition of its inherent safety concept book. Lessons learned in the ensuing years, combined with the fact that inherently safer design (ISD) was becoming more widely accepted, prompted CCPS to update the concept book in 2009. In the subsequent years, inherent safety has been of greater interest to industry, government, and the public as a concept to reduce hazards. In fact, several governmental entities have mandated consideration of inherently safer design for certain facilities. In the United States, for example, specific regulations exist now for Contra Costa County in California, the State of New Jersey, and the U.S. Environmental Protection Agency.

Clearly, there is an ongoing need for more guidance, especially in practical, step-wise approaches to conduct inherently safer design studies. This edition builds on the philosophy provided in the first two concept books. It also provides guidelines and approaches to using these concepts with recent research, practitioner observations, new examples and industry methods.

1.1.2 Intended Audience

This book is written for those interested in the application of inherent safety strategies to process safety in industry. It is intended for facility site managers, process safety experts, engineers, chemists, regulators, research and development groups, process development teams, engineering educators and others responsible for workplace safety.

1.1.3 Scope

This book includes key principles on inherent safety and guidelines for how to implement them. It also includes guidance on how to conduct inherent safety studies as well as how to apply inherent safety to an organization's process safety management processes. It also briefly covers the history, research, and basic concepts of inherent safety. The methods described in this book may be widely applicable to inherent safety as it relates to process safety, environmental, and security issues.

1.2 INTEGRATION OF THIS GUIDANCE WITH OTHER CCPS GUIDANCE

Inherent safety is an integral component of process risk management. It is a foundation topic to managing chemical risks and has been referenced in other CCPS guideline books including:

• Guidelines for Safe Storage and Handling of Reactive Materials, 1995.
• Layer of Protection Analysis, Simplified Process Risk Assessment, 2001.
• Guidelines for Identifying and Analyzing the Security Vulnerabilities of Fixed Chemical Sites, 2003.
• Guidelines for Risk-Based Process Safety, 2007.
• Guidelines for Hazard Evaluation Procedures, Third Edition, with Worked Examples, 2007.
• Guidelines for Engineering Design for Process Safety, Second Edition, 2012, includes a section (Chapter 5.2) on inherently safer design.
• Guidelines for Implementing Process Safety Management Systems, Second Edition, 2016.
• Guidelines for Siting and Layout of Facilities, Second Edition, 2018.
• Guidelines for Integrating Process Safety into Engineering Projects, 2019.

1.3 ORGANIZATION OF THE BOOK

The book is written with the key principles for inherent safety in the body of the book. Tools for implementing the approach, as well as indicative examples and checklists, are included in the appendices. The guidelines begin with an explanation of the concept of Inherent Safety (IS) and then explain its role in Process Risk Management.

Chapter 2 introduces the topic of inherent safety. The key terms and the philosophy behind inherent safety are described. The different ways in which inherent safety is applied can be categorized into “strategies.” These strategies—minimize, substitute, moderate, and simplify—are discussed in detail in Chapters 3 through 6. Human factors are an extremely important subset of the simplify strategy, and Chapter 6.11 of this book presents a detailed discussion of human factors as related to inherently safer design for the human-machine interface. Chapter 7 outlines how each of the four IS strategies can be applied to traditional protection layers.

“Inherently safer” is a way of thinking and, to successfully implement it, this thinking must be well-understood and continually employed wherever possible. Improved understanding of the process may result in a better, more reliable, and even more productive and profitable process that produces higher quality products. Processes should be reviewed for hazards and risks periodically throughout their life cycle. Chapters 8 discusses review methods to do this. Chapter 9 discusses the role of inherent safety in chemical process security. Chapter 10 presents available methods for implementing inherently safer strategies. These can either be independent, special studies, done periodically or before a major project or change is undertaken, or opportunistically applied into day-to-day process risk management strategies. Chapter 11 describes the relationship between the four main IS strategies, i.e., Substitution, Minimization, Moderation, and Simplification and each element of a PSM/Risk-Based Process Safety (RBPS) program. Chapter 12 addresses tools available to assist with implementing these IS strategies.

Chapter 13, entitled “Inherently Safer Design Conflicts,” describes the conflicts that often develop between the various attributes of safety, operability, cost, as well as other risk parameters and the ways to understand and make decisions considering those constraints. With the advent of regulations requiring inherent safety consideration or implementation, Chapter 14 was written to help guide regulators and industry through the various considerations and challenges of IS.

Chapter 15 contains worked examples of IS study methods and case studies to show a step-wise process that can be followed for an IS evaluation. It also gives practical examples of successful implementation.

Lastly, Chapter 16 describes potential future IS initiatives, including needs, research, expected practice issues, and regulatory issues.

1.4 HISTORY OF INHERENT SAFETY

Inherent Safety is a modern term for an age-old concept: to progress towards eliminating or reducing hazards rather than accepting and managing them. This concept goes back to prehistoric times. For example, building villages near a river on high ground, rather than managing flood risk with dikes and walls, is an inherently safer design concept.

There are many examples of milestones in the application of inherently safer design. For example, in the United States back in 1866, following a series of explosions involving the handling of nitroglycerine, which was being shipped to California for use in mines and construction, state authorities quickly passed laws forbidding its transportation through San Francisco and Sacramento. This action made it virtually impossible to use the material in the construction of the Central Pacific Railroad.

The railroad desperately needed the explosive to maintain its construction schedule in the mountains. Fortunately, a British chemist, James Howden, approached Central Pacific and offered to manufacture nitroglycerine at the construction site. This is an early example of an inherently safer design principle – minimize the transport of a hazardous material by in-situ manufacture at the point of use. While nitroglycerine still represented a significant hazard to the workers who manufactured, transported, and used it at the construction site, the hazard to the general public from nitroglycerine transport was eliminated. At one time, Howden was manufacturing 100 pounds of nitroglycerine per day at railroad construction sites in the Sierra Nevada Mountains. The Central Pacific Railroad's experience with the use of nitroglycerine was quite good, with no further fatalities directly attributed to use of the explosive during the Sierra Nevada construction (Ref 1.22 Rolt), (Ref 1.2 Bain).

By today's standards, little about 19th Century railroad construction would qualify as safe, but the in-situ manufacture of nitroglycerine by the Central Pacific Railroad did represent an advance in inherent safety for its time. A further, and probably more important advance occurred in 1867, when Alfred Nobel invented dynamite by absorbing nitroglycerine on a carrier, greatly enhancing its stability. This is an application of another principle of inherently safer design – moderate, by using a hazardous material in a less hazardous form (Ref 1.9 Henderson).

A milestone event in process safety and inherent safety was the 1974 Flixborough explosion in the United Kingdom that caused twenty-eight deaths. On December 14, 1977, inspired by this tragic event, Dr. Trevor Kletz, who was at that time safety advisor for the ICI Petrochemicals Division, presented the annual Jubilee Lecture to the Society of Chemical Industry in Widnes, England. His topic was “What You Don't Have Can't Leak,” and this lecture was the first clear and concise discussion of the concept of inherently safer chemical processes and plants.

Following the Flixborough explosion, interest in chemical process industry (CPI) safety increased, from within the industry, as well as from gover...

Table of contents

• Cover
• Title Page
• Copyright
• Dedication
• Preface
• Acknowledgements
• 1 Introduction
• 2 The Concept of Inherent Safety
• 3 Minimize – An Inherently Safer Strategy
• 4 Substitute – An Inherently Safer Strategy
• 5 Moderate – An Inherently Safer Strategy
• 6 Simplify – An Inherently Safer Strategy
• 7 Applying Inherent Safety Strategies to Protection Layers
• 8 Life Cycle Stages
• 9 Inherent Safety and Security
• 10 Implementing Inherently Safer Design
• 11 Inherent Safety & the Elements of a RBPS Program
• 12 Tools for IS Implementation
• 13 Inherently Safer Design Conflicts
• 14 Inherent Safety Regulatory Initiatives
• 15 Worked Examples and Case Studies
• 16 Future Initiatives
• Appendix A. Inherently Safer Technology (IST) Checklist
• Appendix B. Inherent Safety Analysis Approaches
• Glossary
• References
• Index
• End User License Agreement