Trevor Kletz Research Articles

The role of inherently safer design in process safety

AbstractThe role of inherently safer design (ISD) in process safety assurance has changed significantly over the past 40 years. When first introduced by Professor Trevor Kletz following the 1974 Flixborough explosion, the ISD concept challenged the manner in which process risk was addressed in the chemical industry. The prevailing view of adding on safety devices and implementing procedures aimed at controlling hazards was now complemented by a way of thinking that sought to remove or reduce hazards at their source. The past 20 years have seen ISD mature into an established risk reduction strategy that is widely known in principle and increasingly adopted in practice. The current paper reviews the authors' collaborative research efforts aimed at integrating ISD into various process safety systems, activities, and applications. The primary inherent safety principles (minimization, substitution, moderation, and simplification) are explained with example‐based guidance provided for their use. ISD features and performance indices are examined throughout the early design and operational stages of a typical process life cycle. Preventing and mitigating undesirable occurrences such as domino effects and dust explosions are shown to be feasible by adopting an inherent safety approach. The importance of reviewing ISD case studies developed from incident investigations is also discussed. Finally, we present our personal opinions on the current status of inherently safer design and future possibilities for its continued growth.

The importance of (process safety) leadership

It is indeed an honour to be invited to contribute the inaugural Trevor Kletz & Sam Mannan Guest Perspective on Process Safety. Unfortunately I did not ever meet Trevor, though I worked at a plant he was a design consultant on, but I worked with Sam for several years, together focused on how we could improve process safety outcomes.For this paper I want to write about a key area in process safety that I believe underpins everything we do. If we get it really wrong, we can't come back from the brink. If we get it a little wrong, we can usually recover, with a lot of work and effort. If we get it right, things just work. So, what am I talking about, is it design, maintenance, operations? No, I am talking about leadership. This underpins everything else we do in process safety yet is an oft neglected aspect. I think this is a fitting start to this series, because both Trevor and Sam believed in effective communication, which is a key element of leadership. I hope it will set the scene for future articles to incorporate aspects of leadership when others will delve into more detailed topics.

Trevor Kletz's scholarly legacy: A co-citation analysis

Dr. Kletz is one the pioneers in the process safety area, known widely for his work on inherent safety design and loss prevention. He worked 38 years in Imperial Chemical Industries, and became a fulltime researcher only after his retirement. He published more than 200 papers and 15 books during his retirement. The intellectual basis analysis presented in this article shows that he frequently cited his books in his articles, indicating that his industrial experience was very influential to his scholarly contributions. Lawley, H.G. was one of the researchers whose work had most influence on Kletz's research. Among Dr. Kletz's publications, the article ‘What You Don't Have, Can't Leak’ has the highest impact, while his most influential book is ‘Process plants: A handbook for inherently safer design’. The references co-citation network is divided in two clearly connected components: his earlier work related to infra-red spectra, and his later work addressing process safety related topics, including inherent safety and hazard and accident analysis. Both his work and that of his followers is rooted in a similar intellectual basis within process safety research, in which particularly Dr. Kletz's earlier work forms an influential original body of knowledge rooted in his industrial experience. His career is a prime example of how process safety research has been strongly influenced by knowledge from industrial practice, illustrating that a continued strong connection between industry and academia can lead to very fruitful outcomes. It is hoped that the presented analysis can inspire especially young graduates with academic interests to first embark on an industrial career to gain industrial experience before aiming to contribute to academic process safety knowledge.

A critical approach to safety equipment and emergency time evaluation based on actual information from the Bhopal gas tragedy

As amply reported, after Bhopal disaster process safety got a boost worldwide and risk analysis got applied more generally. Even if the concept of inherent safety, strongly promoted by Trevor Kletz, represents one of the main lessons from this tragedy, in the first part of the paper we focus on Bhopal mitigation measures representing the ultimate relevant layer of protection. Starting from a technical analysis of the whole safety equipment of the plant and relevant empirical evidences, we face the short-cut design of critical safety devices suitable to mitigate release effects. The applied method allows a preliminary design and management tool to evaluate the effectiveness of safety systems and the impact on surroundings. In the second part, we develop an empirical-based framework allowing to identify emergency actions and intervention time and demonstrate how the implementation of these safety measures when reaching a critical pressure of 10psig in Tank 610, even under the condition of protective equipment out of commission, would have surely mitigated such a high profile tragedy. The paper illustrates the determining contribution to this tragedy of such deficiencies in the safety procedures for handling abnormal situations and emergencies by the company.

Trevor Kletz, Some Common Errors in Accident Investigations

For a long time many of us have been writing books and papers and giving lectures on the best way to investigate accidents. This paper discusses some of the worst errors that investigators make.1. The worst error: they think of a possible cause and then look for evidence that supports it.2. They quote human error as a cause3. They blame individuals though many people have opportunities to prevent most accidents.4. They report that such an event has never occurred before.5. They keep the report secret.6. They do not realise that the actions are the most important part of a report.7. They say that an accident will never happen again.8. They interview witnesses in the head office.

Trevor Kletz, SaRS Conference, Manchester, 5 July 2011

The reliability of the chemical and oil industries is lower than it could be and is the cause of many accidents. Some of the changes needed, both technical and human, are described. However, reliability cannot be considered in isolation. Increases in reliability can result in lower availability and greater cost. We have to keep three balls in the air.

David M. Clarke MSaRS in Interview with Trevor Kletz, Talking About Safety Part 2

David M. Clarke MSaRS in Interview with Trevor Kletz, Talking About Safety Part 2

David M. Clarke, MSaRS in Interview with Trevor Kletz, Talking About Safety Part 3

David M. Clarke, MSaRS in Interview with Trevor Kletz, Talking About Safety Part 3

David M. Clarke, MSaRS in Interview with Trevor Kletz, Talking About Safety Part 1

David M. Clarke, MSaRS in Interview with Trevor Kletz, Talking About Safety Part 1

Continuing our process safety management journey

Abstract“…in the eyes of the public the industry is one.”Trevor Kletz (b. 1922)Process safety risk reduction efforts are a part of our journey to make our chemical industry safer for people and the environment. This article focuses on our process safety risk reduction efforts, providing (1) a brief historical discussion, (2) a framework for today's current practices, and (3) a proposal for some future efforts. Process safety practices have evolved over the years and continue to evolve today as we share our new practices and theories. In addition, today's digital age continues to enhance our ability to share information across the globe, and it has accelerated the changing nature of the public's view of the chemical industry—the public's concept of acceptable societal risk. Our right to operate chemical facilities is based on several factors, including our effect on neighboring communities, the public's changing perception, and the governmental regulations created in response to major fires, explosions, and toxic releases. © 2012 American Institute of Chemical Engineers Process Saf Prog, 2012

Trevor Kletz, friend and mentor

I am very pleased to have this opportunity to present these thoughts on my personal relationship with Trevor Kletz and the impact he has had on my own career in the field of process safety.

Kletz's legacy for developing countries: Simple systems based on inherently safer design

The now well-known theory surrounding Inherently Safer Design (ISD) developed by Trevor Kletz has spread worldwide thanks to journals and almost unlimited communication between members of process safety all around the globe. This means that developing countries, such as Colombia, now have the possibility of applying it to their specific situations, which can often be resolved if the safety hierarchy is followed in order to attack problems from the design stage, a solution that might not seem instinctive, but is actually effective since there isn't a “reduction” strategy, but a removal of hazards. To apply this methodology to a specific Colombian case study, a previous quantitative risk analysis of an LPG storage tank farm in Colombia is revised and reformulated by developing an optimization (MINLP) based on the principles of inherent safety in order to design the same process (LPG pressurized storage) so that the available engineering tools can be used to mathematically formulate the inherent safety criteria. This allows determining the design conditions and safety measures needed to reduce the likelihood of an incident, being consistent with the Inherent Safety philosophy, which seeks a change of mental structure when designing processes, just like Trevor Kletz proposed and established as a new paradigm for Process Plants/Equipment design. The results of the project allow obtaining a specific optimal configuration of control, wall thickness, operating pressure and tank dimensions, pointing out a decrease of around 20% on the operating pressure.

A journey into Process Safety with Trevor Kletz

I offer a personal perspective on the Process Safety contributions of Trevor Kletz and how his lessons have helped shaped both my career and my own views on the topic.

Toward an inherently safer design and operation of batch and semi-batch processes: The N-oxidation of alkylpyridines

This work shows an application of inherent safety principles to a reaction widely used in the pharmaceutical industry. More specifically, it incorporates the teachings of Trevor Kletz into the design of an inherently safer process for the N-oxidation of alkylpyridines. This reaction is of interest because of the hazards resulting from the undesired, gas-generating decomposition of hydrogen peroxide, the oxidizing agent. The generation of oxygen, combined with the flammability of the alkylpyridines, represents a serious fire and explosion hazard for this process. The purpose of this paper is to demonstrate how an inherently safer process can be potentially achieved by designing improved reactors and by assessing conditions that reduce or eliminate the hazards. Furthermore, it is shown that such improvement in safety increases the efficiency of the process and results in a cost reduction.

A tribute to Trevor Kletz: What we are doing and why we are doing it

The goal of my tribute to Trevor Kletz is to show a view of his overall influence on many of the elements of process safety: how he helped establish a strong foundation on which we are building our future process safety risk reduction efforts.

Engineers need RUDENESS: An extension of trevor Kletz's approach to accident investigations

AbstractTrevor Kletz belongs to the pioneers in root cause analysis of accidents. This article summarizes Kletz's approach to accident investigations, and it points out that his approach has some gaps that sometimes need to be addressed. These gaps seem to be related to certain assumptions taken for granted by Kletz but not always fulfilled in the real world. In general, Kletz assumes that professionals and leaders are honest and responsible. In fact, Kletz deliberately strives to avoid “blaming.” Therefore, Kletz gives no guidance of what to do when leaders' negligence contributes to an accident.This article expands the Kletz approach to include this aspect of process safety. Two acronyms are used to describe the difference between the Kletzian (more ideal) and non‐Kletzian world. The engineering approach that follows Mr. Kletz's vision is depicted by the word RUDE, where R is for Reliable equipment—the need for engineers to provide R; U is for Understanding it—the need for engineers to understand the properties, hazards, and correct use of equipment; D is for Disciplined personnel—the need for leadership to select and support D, E is for Empathy—the need for leaders to recognize the deficiencies and incompetence of their employees.An expanded approach is depicted by the word RUDENESS, where NE is for Navigators in Ethics—the need for the leaders of society to act as role models and stress ethic fundamentals of process safety, and SS is for a Safety‐demanding Society—the need for both government and the governed to place a high priority on safety performance with appropriate laws and standards. © 2012 American Institute of Chemical Engineers Process Saf Prog, 2012

HAZOP study training from the 1970s to today

An account is given of HAZOP study training from the simple methods used initially to modern methods such as e-learning courses. An especial mention is given to the role of Trevor Kletz in initiating public courses.

Trevor Kletz's impact on process safety and a plea for good science – An academic and research perspective

To provide even a short summary of Trevor Kletz’s career The December 1984 disaster in Bhopal was a wake-up all for the industry and a call to arms for all stakeholder roups. Government regulators, industry, academia and all ther stakeholder groups responded to this erstwhile unthinkble disaster with regulatory programs, industry standards, esearch, education and training. Many started talking about nherent safety concepts and other safety barriers that had ailed to cause the tragedy. Trevor Kletz, a quiet and unasuming man with the education and training of a chemist in is own characteristic manner had already been talking about nherent safety concepts much earlier. A decade before the hopal tragedy occurred, Trevor Kletz had published and spoen numerous times about inherent safety concepts in his legantly classic paper with the intriguing title, “What you on’t have can’t leak.” In appearance, a diminutive man, Trevor Kletz is a giant in he field of process safety. He has single-handedly influenced his field more than anyone else has had the opportunity to nfluence their respective fields. Amongst a lot of others, this uthor’s own career has been influenced to a great extent by revor Kletz. I am proud to recognize Trevor as a great friend, eacher and mentor. In this paper, I have tried to shed light n some of Trevor Kletz’s teachings and my opinion of what e might have said about different topics on process safety. ven though the author is indebted to Trevor Kletz for his eachings, the opinions expressed in this paper are solely the uthor’s own. The industrial revolution brought prosperity and along ith it the use of hazardous processes and complex techologies. Growing economies and global competition has led o more complex processes involving the use of hazardous hemicals, exotic chemistry, and extreme operating condiions. The growth of industry and as a result the economy is

What you don’t manage will leak: A tribute to Trevor Kletz

This paper expands on a simple concept shared with us over three decades ago by Trevor Kletz: what you don’t have can’t leak. Despite many efforts at eliminating hazards through inherently safer process methodologies, as encouraged by Kletz and others, the reality is that the use of hazardous materials and processes is still quite common. Therefore, we consider those processes that still handle hazardous materials – the cases where what you do not manage will leak and may cause a fire, explosion or toxic release. Our intended audience is quite broad. As Kletz has noted over the years, it is not just the people running a process who are responsible for its safety, but also those who make decisions on its design, operation, maintenance, staffing, etc. We hope that this paper contributes to an understanding of why we continue to have hazardous materials leak, potentially leading to accidents that cause fatalities, serious injuries, property damage, and environmental harm.We expand on the fundamental equation for risk, a function of both the frequency and the consequence of a possible event, by considering the effects of poor operational discipline on risk, and ultimately, on the possible leak or release of the hazardous material. Continued safe operation involving hazardous materials depends on and is sustained by the operational discipline of everyone involved in the design of processes and their continuing operation and maintenance. What we do not manage will leak and therein lays the fundamental challenge that Kletz continues to emphasize today.

Tanks A Lot – Trevor: For enduring process safety contributions

Trevor Kletz has left an indelible mark on worldwide chemical process safety. He generously shared his insight for decades and I have been fortunate to have spent my process safety career in the shadow of Trevor Kletz’s influence. In the early 1980s I purchased one of the first commercially available process safety awareness training modules. The module was entitled the “Hazards of Over and Under Pressurizing Tanks,” developed by Trevor, and distributed by the Institution of Chemical Engineers (IChemE). The module contained a collection of short case histories and each incident provided a message on fundamentals. It was an easy to use module with a couple of dozen vivid 35 mm slides and focused on the frail nature of tanks.This paper, “Tanks A Lot – Trevor” mimics the IChemE approach of three decades ago and could serve as an introductory awareness lesson for the newbie or trainee who desires to learn about the frail nature of tanks. But most likely, it will serve as a reminder to the seasoned reader of things he or she has previously seen or worse yet, experienced.Storage tanks in chemical plants, oil refineries, related distribution terminals and pressure vessels associated in these industries are vital components and a major investment within their facilities. These essential vessels come in all sizes and many shapes and are built to various codes. They may hold large inventories of hazardous materials.Tanks can and do very safely contain a wide variety of raw materials, intermediates and finished products for years. If the tank or its accessories are poorly designed, abused by operations or are neglected with respect to effective inspection and basic maintenance, bad things can happen.This paper includes a few tank system fundamentals as well as case histories of failures in design, operation, inspection and maintenance. Previous vessel incidents must be understood.