Basic Guide to System Safety (4^th Ed.)

Instructional guide applying ?prevention through design? concepts to the design and redesign of work premises, tools, equipment, and processes

Basic Guide to System Safety provides guidance on including prevention through design concepts within an occupational safety and health management system; through the application of these concepts, decisions pertaining to occupational hazards and risks can be incorporated into the process of design and redesign of work premises, tools, equipment, machinery, substances, and work processes, including their construction, manufacture, use, maintenance, and ultimate disposal or reuse. These techniques provide guidance for a life-cycle assessment and design model that balances environmental and occupational safety and health goals over the lifespan of a facility, process, or product.

The updated Fourth Edition reflects current and emerging industry practices and approaches, providing an essential periodic review of the text to ensure its contents adequately meet the requirements of academia as well as other users in the occupational safety and health profession. The book also features a new chapter on Prevention through Design (PtD) and how it is linked to System Safety Engineering and Analysis.

Topics covered in Basic Guide to System Safety include:

• System safety criteria, including hazard severity and probability, the hazard risk matrix, and system safety precedence
• System safety efforts, including closed-loop hazard tracking systems, accident risk assessments, and mishap, accident, and incident reporting
• Fault or functional hazard analysis, management oversight and risk trees, HAZOP and what-if analyses, and energy trace and barrier analysis (ETBA)
• Sneak circuit analysis, including types and causes of sneaks, input requirements, and advantages and disadvantages of the technique

Providing essential fundamentals for readers who may not have a background or pre-requisite in the subject, Basic Guide to System Safety is an ideal introductory resource for the practicing safety and health professionals, along with advanced students taking industrial safety courses.

Preface to the Fourth Edition xiii

Acknowledgments xvi

Part I The System Safety Program 1

1 System Safety: An Overview 3

Background 3

The Difference Between Industrial Safety and System Safety (Leveson 2005) 7

System Safety and the Assessment of Risk 9

2 System Safety Concepts 15

Fundamentals 15

The System Safety Process 16

System Safety Criteria 18

Hazard Severity 18

Hazard Probability 19

The Hazard Risk Matrix 20

System Safety Precedence 22

Cost and Risk Acceptance 25

Quantitative Risk Assessment 28

Principles of Risk Management 29

Management Commitment 30

3 System Safety Program Requirements 32

The Safety Charter 32

Selling Safety to Management 33

The System Safety Effort 34

Life Cycle Phases and the System Safety Process 40

4 The Industrial Safety Connection 44

The Occupational Safety and Health Act 44

The Human Factors Element 46

Accident Prevention Through System Design 47

The Process of Task Analysis 52

The Job Safety Analysis and System Safety 53

Guidelines for Preparing a Job Safety Analysis 56

Signatures and Approvals 61

Attachments to the JSA Form 62

Changes in Hazard/Scope 62

System Safety: An Integral Part of the Overall Organization 62

5 Probability Theory and Statistical Analysis 66

Introduction 66

Probability 67

Statistics 70

Summary 73

Part II System Safety Analysis: Techniques and Methods 75

6 Preliminary Hazard Analysis 77

Introduction 77

The PHA Development Process 78

The Preliminary Hazard Analysis Report 84

PHA Example 84

System Description 85

System Operation 86

Preliminary Assessment 87

Evaluation of System Risk 87

Summary 96

7 Subsystem and System Hazard Analyses 97

Introduction 97

The SSHA Report 98

SSHA Example 99

System Description 100

Evaluation of Subsystem Hazard Risk 101

Summary 104

8 Operating and Support Hazard Analysis 105

Introduction 105

Ergonomics 105

When to Perform the O&SHA 108

O&SHA Example 110

Scope and Purpose of the Example O&SHA 110

Risk Assessment 110

Risk Assessment 1: 1B 112

Risk Assessment 2: 1A 113

Risk Assessment 3: 2B 114

Summary 116

9 Energy Trace and Barrier Analysis 117

Introduction 117

The Energy-Barrier Concept 117

Uses of the ETBA 118

Performing the ETBA 118

The ETBA Worksheet 119

ETBA Example 120

System Description 120

The ETBA 120

Summary 124

10 Failure Mode and Effect Analysis 126

Introduction 126

Types of FMEAs 126

Performing an FMEA 127

The FMEA Report 129

FMEA Example 131

System Component/Subassembly Description 131

Subsystem: Hoist Assembly 131

Component: Electric Hoist Motors and Controls 132

Component: Magnetorque Electric Load Brake 133

Component: Motor Brake Assembly 133

Component: Hoist Gear Reduction Assembly and Wire Rope Drum 133

Subsystem: Motor-Driven Power Wheel 134

Subsystem: Trolley Drive Assembly 134

Subsystem: Bridge Drive Assembly 134

Subsystem: Control Station 134

Subsystem: 1.5 Ton Crane Micro-Drive System 135

Passive Components 135

System Operation 136

Failure Mode(s) and Effect(s) 136

Evaluation of Potential Subsystem or Component Failures 138

Summary 141

11 Fault or Functional Hazard Analysis 142

Introduction 142

The FHA Process 143

FHA Example 144

System Description 144

The FHA Process 147

The FHA 147

Summary 148

12 Fault Tree Analysis 150

Introduction 150

Qualitative and Quantitative Reasoning 151

Constructing a Fault Tree 151

Fault Tree Symbols 153

FTA Examples 155

Probability Values and the Fault Tree 159

Summary 162

13 Management Oversight and Risk Tree 164

Introduction 164

The MORT Analytical Chart 165

MORT Use 166

The MORT Event Tree 167

Symbols 168

MORT Analysis Example 168

MORT Color Coding 170

Procedure for MORT Analysis 171

Summary 173

14 HAZOP and What-If Analyses 174

Introduction 174

Background 175

Definitions 175

Objectives 176

Team Members 176

Reference Data Requirements 177

The Concept of “Nodes” 177

Conducting the What-If Analysis 178

What-If Analysis Steps 179

The What-If Analysis Worksheet 180

Conducting the HAZOP Study 183

The HAZOP Worksheet 183

The Analysis Report 185

Summary 185

15 Special Use Analysis Techniques 188

Introduction 188

Sneak Circuit Analysis 189

Types and Causes of Sneaks 189

SCA Input Requirements 190

Advantages and Disadvantages of the SCA 192

Software Hazard Analysis 193

Types of SWHA Techniques 193

The Software Preliminary Hazard Analysis 193

Software Fault Hazard Analysis 194

Software Fault Tree (“Soft Trees”) 194

Emulation Analysis 195

Software System Hazard Analysis 195

Summary 195

16 Prevention Through Design and the Prevention of Incidents 197

Introduction 197

Incident Prevention Through Design and Planning 198

Historical Case Study – The Design of WW-II Bombers 198

Design Failures or Oversights Can Also Impact the Production Phase 200

Risk Mitigation 200

The Owner 201

The Design Team 203

The Construction Team 204

Safety Planning 205

The Safety Management Paradox 205

The Problem 206

The Solution 207

Summary 207

Epilogue 209

Acronyms and Abbreviations 211

Glossary of Terms 215

Bibliography 241

Index 243

Jeffrey W. Vincoli is currently Managing Consultant for Technical Services with Progressive Safety Management. In this position, he provides consultative support for clients in the subject areas of Compliance Assessments, Incident Investigations, and Expert Witness Services. Prior to joining Progressive Safety Management in 2019, Jeff worked as Director of Compliance for ESH&QA for a Bechtel affiliate company known as Welded Construction, a pipeline contractor based in Ohio.