Barriers And Accident Prevention

by Hollnagel,Erik

• ISBN13: 9780754643012
• ISBN10: 0754643018
• Format: Hardcover
• Copyright: 2004-10-28
• Publisher: Routledge

Summary

Accidents are preventable, but only if they are correctly described and understood. Since the mid-1980s accidents have come to be seen as the consequence of complex interactions rather than simple threads of causes and effects. Yet progress in accident models has not been matched by advances in methods. The author's work in several fields (aviation, power production, traffic safety, healthcare) made it clear that there is a practical need for constructive methods and this book presents the experiences and the state-of-the-art.The focus of the book is on accident prevention rather than accident analysis and unlike other books, has a proactive rather than reactive approach. The emphasis on design rather than analysis is a trend also found in other fields.Features of the book include:-A classification of barrier functions and barrier systems that will enable the reader to appreciate the diversity of barriers and to make informed decisions for system changes.-A perspective on how the understanding of accidents (the accident model) largely determines how the analysis is done and what can be achieved. The book critically assesses three types of accident models (sequential, epidemiological, systemic) and compares their strengths and weaknesses.-A specific accident model that captures the full complexity of systemic accidents. One consequence is that accidents can be prevented through a combination of performance monitoring and barrier functions, rather than through the elimination or encapsulation of causes.-A clearly described methodology for barrier analysis and accident prevention.Written in an accessible style, Barriers and Accident Prevention is designed to provide a stimulating and practical guide for industry professionals familiar with the general ideas of accidents and human error. The book is directed at those involved with accident analysis and system safety, such as managers of safety departments, risk and safety consultants, human factors professionals, and accident investigators. It is applicable to all major application areas such as aviation, ground transportation, maritime, process industries, healthcare and hospitals, communication systems, and service providers.

Author Biography

Erik Hollnagel has been a Full Professor of Human-Machine Interaction at Linkoping University, (S) since 1999.

Table of Contents

PREFACE	x
What is this Book About?	xi
Readership and Outline	xii
Acknowledgements	xvi
CHAPTER 1: ACCIDENTS AND CAUSES
INTRODUCTION	1	(9)
What is an Accident?	3	(1)
A Little Etymology	4	(6)
Definition of Accident	5	(2)
Accidents versus Good Luck	7	(1)
Accident as Noun and as Verb	8	(2)
ACCIDENTS, CAUSES AND CONSEQUENCES	10	(15)
Unwanted Outcomes	10	(3)
Lack of Unwanted Outcome	13	(1)
Unexpected Events	13	(3)
Beyond Design-Base Accidents	15	(1)
Intended Acts and Unintended Outcomes	16	(1)
The Grounding of s/s Stockholm	17	(3)
Accidents, Incidents, and Near Misses	20	(5)
THE SEARCH FOR CAUSES	25	(11)
Facts and Explanations	26	(1)
The Difference between Explanations and Causes	27	(2)
From Technological Failure to 'Human Error'	29	(2)
Causality and Time	31	(1)
Evolving Concepts of Causes	32	(2)
A Cynical Definition of Causes	34	(2)
CHAPTER 2: THINKING ABOUT ACCIDENTS
INTRODUCTION	36	(8)
The Search for Causes in Science and Philosophy	38	(3)
The Big Bang	39	(2)
Causality	41	(3)
THE NEED FOR ACCIDENT MODELS	44	(24)
Sequential Accident Models	47	(7)
The Root Cause	51	(3)
Epidemiological Accident Models	54	(5)
Performance Deviations	54	(1)
Environmental Conditions	54	(1)
Barriers	54	(1)
Latent Conditions	55	(4)
Systemic Accident Models	59	(6)
The Sharp End and the Blunt End	62	(3)
Consequences of Systemic Models	65	(1)
Comments to the Models	65	(3)
CHAPTER 3: BARRIER FUNCTIONS AND BARRIER SYSTEMS
INTRODUCTION	68	(10)
Origin of Barriers	69	(2)
Barrier Examples	71	(1)
Getting In and Out of Doors	72	(4)
Accidents in Sweden	73	(3)
Barriers and Accidents	76	(2)
USE AND DESCRIPTION OF BARRIERS	78	(7)
The Prevention of Accidents	79	(1)
Barriers and MORT	79	(2)
The Barrier Concept in Risk Analysis	81	(1)
The Accident Evolution and Barrier (AEB) Model	82	(1)
Barriers and Latent Failures	83	(1)
Barriers in Software Systems	84	(1)
CLASSIFICATION OF BARRIERS	85	(12)
Classification Based on the Origin of Barrier	85	(1)
Classification Based on Purpose of Barrier	86	(1)
Classification Based on Barrier Location	86	(1)
A Classification of Barrier Systems	87	(2)
A Classification of Barrier Functions	89	(5)
Composite Barrier Systems	94	(2)
Bus Doors Revisited	96	(1)
BARRIER ANALYSIS AND BARRIER DESIGN	97	(9)
Barrier Quality	97	(7)
Physical Barrier Systems	99	(1)
Functional Barrier Systems	100	(1)
Symbolic Barrier Systems	101	(1)
Incorporeal Barrier Systems	102	(2)
Barriers and Failure Modes	104	(2)
OTHER TYPES OF BARRIERS	106	(3)
Organisational Barriers	107	(2)
CHAPTER 4: UNDERSTANDING THE ROLE OF BARRIERS IN ACCIDENTS
INTRODUCTION	109	(1)
REPRESENTATION OF BARRIERS IN ACCIDENT ANALYSIS	110	(19)
Fault trees	112	(3)
Wrong Drug Dispensed	114	(1)
Event Trees	115	(2)
Fault Trees and Event Trees Compared	117	(4)
The AEB Model	118	(1)
Variation Diagrams	119	(2)
Representing Barriers in Accident Descriptions	121	(2)
The Limitation of Graphical Representations	123	(6)
The Systemic View	124	(5)
COMPLEXITY OF BARRIER FUNCTIONS	129	(6)
Reciprocity	129	(1)
Barrier Bypass	130	(2)
Unintended Barriers	132	(1)
Bi-Directional Barriers	133	(2)
BARRIERS AND ACCIDENT PREVENTION	135	(5)
Responding to Accidents	136	(4)
CHAPTER 5: A SYSTEMIC ACCIDENT MODEL
INTRODUCTION	140	(4)
Time and Variability	142	(2)
THE PRINCIPLE OF EFFICIENCY-THOROUGHNESS TRADE-OFF	144	(15)
Nominal and Actual Conditions of Work	145	(2)
The Paradox of Optimal Performance	147	(2)
The Need for Local Optimisation	149	(1)
Why Things (Sometimes) go Wrong	150	(2)
ETTO Rules	152	(4)
ETTO on the Level of Cognitive Functioning	153	(1)
ETTO on the Level of Individual Fork	154	(2)
ETTO on the Organisation Level	156	(1)
ETTO in Practice	156	(3)
The Sources of Success	159	(1)
STOCHASTIC RESONANCE AS A MODEL FOR ACCIDENTS	159	(18)
Tacoma Narrows Bridge	162	(1)
London Millennium Bridge	163	(1)
Stochastic Resonance	164	(3)
Resonance in Complex Systems	167	(3)
From Stochastic to Functional Resonance	170	(3)
Functional Resonance Accident Model (FRAM)	173	(4)
About FRAM
CHAPTER 6: ACCIDENT PREVENTION
INTRODUCTION	177	(8)
The Reality of Risks	178	(3)
Requisite Imagination	181	(2)
Harnessing Imagination	183	(2)
ACCIDENT PREDICTION	185	(15)
Step One: Identify Essential System Functions	187	(2)
Step Two: Determine the Potential for Variability	189	(4)
Common Performance Conditions	190	(3)
Step Three: Define Functional Resonance Based on Dependencies among Functions	193	(6)
Finding the Expected Connections	194	(2)
Finding the Unexpected Connections	196	(3)
Step Four: Deciding on Countermeasures	199	(1)
PERFORMANCE VARIABILITY MANAGEMENT	200	(5)
Detection and Control of Performance Variability	201	(4)
THE RECEDING SHARP END	205	(4)
BIBLIOGRAPHY	209	(7)
AUTHOR INDEX	216	(3)
SUBJECT INDEX	219