Evaluation of the Effects and Consequences of Major Accidents in Industrial Plants (eBook)

Cover 1
Table of Contents 10
Preface 8
Chapter 1. Introduction 16
1. Risk 16
2. Risk analysis 17
3. Major accidents 20
3.1 Types 20
3.2 Damage 24
4. Domino effect 27
4.1 Classification of domino effects 27
4.2 An example case 27
5. Mathematical modelling of accidents 29
Nomenclature 31
References 31
Chapter 2. Source term 34
1. Introduction 34
2. Liquid release 36
2.1 Flow of liquid through a hole in a tank 36
2.2 Flow of liquid through a pipe 39
2.2.1 Liquid flow rate 39
2.2.2 Friction factor 42
3. Gas/vapour release 45
3.1 Flow of gas/vapour through a hole 45
3.1.1 Critical velocity 45
3.1.2 Mass flow rate 48
3.1.3 Discharge coefficient 48
3.2 Flow of gas/vapour through a pipe 50
3.3 Time-dependent gas release 55
4. Two-phase flow 57
4.1 Flashing liquids 57
4.2 Two-phase discharge 58
5. Safety relief valves 59
5.1 Discharge from a safety relief valve 60
6. Relief discharges 62
6.1 Relief flow rate for vessels subject to external fire 63
6.2 Relief flow rate for vessels undergoing a runaway reaction 64
7. Evaporation of a liquid from a pool 68
7.1 Evaporation of liquids 68
7.2 Pool size 68
7.2.1 Pool on ground 68
7.2.2 Pool on water 68
7.3 Evaporation of boiling liquids 68
7.4 Evaporation of non-boiling liquids 69
8. General outflow guidelines for quantitative risk analysis 70
8.1 Loss-of-containment events in pressurized tanks and vessels 71
8.2 Loss-of-containment events in atmospheric tanks 71
8.3 Loss-of-containment events in pipes 71
8.4 Loss-of-containment events in pumps 71
8.5 Loss-of-containment events in relief devices 71
8.6 Loss-of-containment events for storage in warehouses 72
8.7 Loss-of-containment events in transport units in an establishment 72
8.8 Pool evaporation 72
8.9 Outflow and atmospheric dispersion 73
Nomenclature 73
References 74
Chapter 3. Fire accidents 76
1. Introduction 76
2. Combustion 76
2.1 Combustion reaction and combustion heat 77
2.2 Premixed flames and diffusion flames 78
3. Types of fire 78
3.1 Pool fires 79
3.2 Jet fires 80
3.3 Flash fires 80
3.4 Fireballs 81
4. Flammability 81
4.1 Flammability limits 81
4.1.1 Estimation of flammability limits 82
4.1.2 Flammability limits of gas mixtures 84
4.1.3 Flammability limits as a function of pressure 85
4.1.4 Flammability limits as a function of temperature 85
4.1.5 Inerting and flammability diagrams 86
4.2 Flash point temperature 87
4.3 Autoignition temperature 88
5. Estimation of thermal radiation from fires 89
5.1 Point source model 89
5.2 Solid flame model 92
5.2.1 View factor 93
5.2.2 Emissive power 95
6. Flame size 98
6.1 Pool fire size 99
6.1.1 Pool diameter 99
6.1.2 Burning rate 101
6.1.3 Height and length of the flames 102
6.1.4 Influence of wind 102
6.2 Size of a jet fire 105
6.2.1 Jet flow 105
6.2.2 Shape and size of the jet fire 107
6.2.3 Influence of wind 109
6.3 Flash fire 114
7. Boilover 115
7.1 Tendency of hydrocarbons to boilover 117
7.2 Boilover effects 118
8. Fireball 119
8.1 Fireball geometry 119
8.1.1 Ground diameter 119
8.1.2 Fireball duration and diameter 119
8.1.3 Height reached by the centre of the fireball 120
8.2 Thermal features 121
8.2.1 Radiant heat fraction 121
8.2.2 Emissive power 122
8.2.3 View factor 123
8.3 Constant or variable D, H and E 123
9. Example case 124
Nomenclature 128
References 130
Chapter 4. Vapour cloud explosions 134
1. Introduction 134
2. Vapour clouds 135
3. Blast and blast wave 136
3.1 Blast wave 136
3.2 Detonations 137
3.3 Deflagrations 138
3.4 Blast scaling 138
3.5 Free-air and ground explosions 139
4. Estimation of blast: TNT equivalency method 140
5. Estimation of blast: multi-energy method 144
6. Estimation of blast: Baker-Strehlow-Tang method 148
7. Comparison of the three methods 151
8. A statistical approach to the estimation of the probable number of fatalities in accidental explosions 153
9. Example case 155
Nomenclature 159
References 159
Chapter 5. BLEVEs and vessel explosions 162
1. Introduction 162
2. Mechanism of BLEVE 164
2.1 Liquid superheating 166
2.2 Superheat limit temperature 168
2.3 Superheat limit temperature from energy balance 171
2.4 When is an explosion a BLEVE? 174
3. Vessel failure 178
3.1 Mechanism 178
3.2 Pressure required for vessel failure 179
4. Estimation of explosion effects 180
4.1 Thermal radiation 180
4.2 Mechanical energy released by the explosions 180
4.2.1 Ideal gas behaviour and isentropic expansion 181
4.2.2 Real gas behaviour and irreversible expansion 183
4.3 Pressure wave 184
4.4 Using liquid superheating energy for a quick estimation of .P 188
4.5 Estimation of .P from characteristic curves 191
4.6 Missiles 193
4.6.1 Range 196
4.6.2 Velocity 197
5. Preventive measures 198
6. Example cases 201
Nomenclature 205
References 207
Chapter 6. Atmospheric dispersion of toxic or flammable clouds 210
1. Introduction 210
2. Atmospheric variables 210
2.1 Wind 211
2.2 Lapse rates 214
2.3 Atmospheric stability 215
2.4 Relative humidity 219
2.5 Units of measurement 219
3. Dispersion models 220
3.1 Continuous and instantaneous releases 220
3.2 Effective height of emission 222
4. Dispersion models for neutral gases (Gaussian models) 223
4.1 Continuous emission 224
4.2 Instantaneous emission 230
4.3 Short-term releases 233
5. Dispersion models for heavier-than-air gases 234
5.1 Britter and McQuaid model 236
5.1.1 Continuous release 236
5.1.2 Instantaneous release 238
5.1.3 Finite duration release 240
6. Calculating concentration contour coordinates 242
6.1 The Ooms integral plume model 242
6.2 Determining concentration contour coordinates 242
7. Dispersion of dust 245
8. Atmospheric dispersion of infectious agents 246
8.1 Emission source 246
8.2 Dispersion of airborne pathogenic agents 247
8.3 Epidemics: dispersion of airborne viruses 247
9. Escaping 251
10. Sheltering 251
10.1 Concentration indoors 251
10.1.1 Continuous release 251
10.1.2 Temporary release 252
10.1.3 Instantaneous release 254
10.1.3 A simplified approach 256
11. Example case 257
Nomenclature 259
Annex 6-1 261
References 262
Chapter 7. Vulnerability 264
1. Introduction 264
2. Population response to an accident 264
3. Probit analysis 265
4. Vulnerability to thermal radiation 269
4.1 Damage to people 269
4.1.1 Probit equations 272
4.1.2 Clothing 273
4.1.3 Escape 273
4.1.4 Effect of hot air 276
4.2 Material damages 276
5. Vulnerability to explosions 278
5.1 Damage to human beings 278
5.1.1 Direct consequences 278
5.1.2 Indirect consequences 280
5.1.3 Collapse of buildings 283
5.2 Consequences of an explosion for buildings and structures 284
6. Vulnerability to toxic substances 286
6.1 Dose and probit equations 288
6.2 Substances released from a fire 290
7. Inert gases 292
8. Influence of sheltering 294
8.1 Thermal radiation 294
8.2 Blast 295
8.3 Toxic exposure 295
9. Relationship between the number of people killed and the number of people injured in major accidents 295
10. Zoning according to vulnerability 296
11. Example case 298
Nomenclature 301
Annex 7-1 302
References 303
Chapter 8. Quantitative risk analysis 306
1. Introduction 306
2. Quantitative risk analysis steps 307
3. Individual and societal risks 309
3.1 Individual and societal risks definition 309
4. Risk mapping 311
4.1 Individual risk contours 311
4.2 Procedure 311
4.3 Societal risk 313
5. Introductory examples of risk calculation 314
6. Frequencies and probabilities 321
6.1 Frequencies of most common loss-of-containment events 321
6.2 Failure of repression systems 321
6.3 Human error 321
6.4 Probabilities for ignition and explosion of flammable spills 321
6.5 Meteorological data 324
7. Example case 324
7.1 Estimation of the frequencies of initiating events 326
7.2 Event trees of the diverse initiating events 327
7.3 Effects of the different accident scenarios 334
7.4 Calculation of the individual risk 342
Nomenclature 344
References 346
Annex 1 Constants in the Antoine equation 348
Annex 2 Flammability limits, flash temperature and heat of combustion (higher value) for different substances 350
Annex 3 Acute Exposure Guideline Levels (AEGLs) 352
Annex 4 Immediately Dangerous to Life and Health concentrations (IDLH) 360
Annex 5 Determining the damage to humans from explosions using characteristic curves 362
Damage to humans from explosions as a function of TNT equivalence 362
Damage to humans from vapour cloud explosions as a function of the Multi-energy method 364
References 366
Index 368