Chemical Process Safety

Preface xv

About the Authors xviii

Nomenclature xx



Chapter 1: Introduction 1

1-1 Engineering Ethics 6

1-2 Myths about Process Safety 7

1-3 Safety Culture 10

1-4 Individual Risk, Societal Risk, and Risk Populations 13

1-5 Voluntary and Involuntary Risk 14

1-6 Safety Metrics 15

1-7 Accident and Loss Statistics 17

1-8 Risk Perception 27

1-9 Risk Tolerance/Acceptance and Risk Matrix 27

1-10 Codes, Standards, and Regulations 31

1-11 Safeguards 33

1-12 The CCPS 20 Elements of Risk-Based Process Safety 36

1-13 Inherently Safer Design 42

1-14 The Worst Chemical Plant Tragedy: Bhopal, India, 1984 46

1-15 Overview of Chemical Process Safety 49

Suggested Reading 49

Problems 50



Chapter 2: Toxicology 55

2-1 How Toxicants Enter the Body 56

2-2 How Toxicants Are Eliminated from the Body 59

2-3 Effects of Toxicants on the Body 60

2-4 Toxicological Studies 61

2-5 Dose versus Response 62

2-6 Dose and Response Using Probit Equation 68

2-7 Relative Toxicity 74

2-8 Threshold Limit Values 75

Online Resources 76

Suggested Reading 77

Problems 77



Chapter 3: Industrial Hygiene 79

3-1 Anticipating and Identifying Hazardous Workplace Exposures 80

3-2 Globally Harmonized System 83

3-3 Evaluate the Magnitude of Exposures and Responses 89

3-4 Develop and Evaluate Control Techniques to Prevent Exposures 106

3-5 National Fire Protection Association Diamond 115

Online Resources 116

Suggested Reading 117

Problems 117



Chapter 4: Source Models 119

4-1 Introduction to Source Models 121

4-2 Flow of Liquid through a Hole 123

4-3 Flow of Liquid through a Hole in a Tank 126

4-4 Flow of Liquids through Pipes 130

4-5 Flow of Gases or Vapors through Holes 140

4-6 Flow of Gases or Vapors through Pipes 145

4-7 Flashing Liquids 162

4-8 Liquid Pool Evaporation or Boiling 168

4-9 Realistic and Worst-Case Releases 169

4-10 Conservative Analysis 169

Suggested Reading 172

Problems 173



Chapter 5: Hazardous Material Dispersion 177

5-1 Parameters Affecting Dispersion 178

5-2 Neutrally Buoyant Dispersion Models 183

5-3 Pasquill-Gifford Model 184

5-4 Dense Gas Dispersion 197

5-5 Toxic Effect Criteria 198

5-6 Release Prevention and Mitigation 209

Suggested Reading 212

Problems 212



Chapter 6: Fires and Explosions 219

6-1 The Fire Triangle 220

6-2 Distinction between Fires and Explosions 221

6-3 Definitions 221

6-4 Flammability Characteristics of Liquids and Vapors 224

6-5 Flammability Characteristics of Dusts 247

6-6 Sprays and Mists 248

6-7 Ignition Energy 248

6-8 Ignition Sources 250

6-9 Experimental Characterization of Gas/Vapor and Dust Explosions 251

6-10 Explosions 258

Suggested Reading 278

Problems 278



Chapter 7: Concepts to Prevent Fires and Explosions 283

7-1 Inerting 284

7-2 Static Electricity 299

7-3 Controlling Static Electricity 315

7-4 Explosion-Proof Equipment and Instruments 323

7-5 Ventilation 325

7-6 Sprinkler Systems 329

7-7 Industry's Fire and Explosion Protection Strategy 332

Suggested Reading 334

Problems 334



Chapter 8: Chemical Reactivity 337

8-1 Background Understanding 338

8-2 Commitment, Awareness, and Identification of Reactive Chemical Hazards 340

8-3 Characterization of Reactive Chemical Hazards Using Calorimeters 346

8-4 Controlling Reactive Hazards 372

Suggested Reading 374

Problems 374



Chapter 9: Introduction to Reliefs 379

9-1 Relief Concepts 380

9-2 Definitions 381

9-3 Code Requirements 383

9-4 Relief System Design 386

9-5 Relief Types and Characteristics 391

9-6 Relief Installation Practices 400

9-7 Relief Effluent Handling 403

Suggested Reading 406

Problems 406



Chapter 10: Relief Sizing 411

10-1 Set Pressure and Accumulation Limits for Reliefs 413

10-2 Relief Sizing for Liquid Service 415

10-3 Relief Sizing for Vapor and Gas Service 422

10-4 Two-Phase Flow during Runaway Reaction Relief 428

10-5 Deflagration Venting for Dust and Vapor Explosions 434

10-6 Venting for Fires External to the Process 440

10-7 Reliefs for Thermal Expansion of Process Fluids 444

Suggested Reading 447

Problems 449



Chapter 11: Hazards Identification and Evaluation 453

11-1 Introduction to Hazard Identification/Evaluation and Risk Analysis 455

11-2 Non-Scenario-Based Hazard Identification/Evaluation Methods 463

11-3 Scenario-Based Hazard Identification/Evaluation Methods 471

11-4 Documentation and Actions Required for Hazard Identification and Evaluation 483

Suggested Reading 483

Problems 483



Chapter 12: Risk Analysis and Assessment 487

12-1 Review of Probability Theory 487

12-2 Event Trees 501

12-3 Fault Trees 506

12-4 Bow-Tie Diagrams 513

12-5 Quantitative Risk Analysis 514

12-6 Layer of Protection Analysis 515

12-7 Risk Assessment 526

Suggested Reading 530

Problems 530



Chapter 13: Safety Strategies, Procedures, and Designs 533

13-1 Process Safety Strategies 533

13-2 Safe Operating Procedures 537

13-3 Safe Work Practices 538

13-4 Designs for Process Safety 541

13-5 Designs for Runaway Reactions 547

13-6 Designs and Practices for the Safe Handling of Dusts 548

Suggested Reading 549

Problems 550



Chapter 14: Case Histories and Lessons Learned 551

14-1 Process Safety Culture 552

14-2 Compliance with Standards 553

14-3 Process Safety Competency 554

14-4 Workplace Involvement 555

14-5 Stakeholder Outreach 556

14-6 Process Knowledge Management 556

14-7 Hazard Identification and Risk Analysis 557

14-8 Operating Procedures 558

14-9 Safe Work Practices 559

14-10 Asset Integrity and Reliability 560

14-11 Contractor Management 561

14-12 Training and Performance Assurance 562

14-13 Management of Change 563

14-14 Operational Readiness 564

14-15 Conduct of Operations 565

14-16 Emergency Management 566

14-17 Incident Investigation 567

14-18 Measurement and Metrics 569

14-19 Auditing 570

14-20 Management Review and Continuous Improvement 570

14-21 Summary 571

Suggested Reading 571

Problems 572



Appendix A: Unit Conversion Constants 573

Appendix B: Flammability Data for Selected Hydrocarbons 577

Appendix C: Saturation Vapor Pressure Data 583

Appendix D: Special Types of Reactive Chemicals 585

Appendix E: Hazardous Chemicals Data for a Variety of Chemical Substances 591

Appendix F: Process Diagrams 599



Index 603