Tunnel Fire Dynamics

Tunnel Fire Dynamics

Haukur Ingason Ying Zhen Li Anders Lönnermark Tunnel Fire Dynamics 1 3

Haukur Ingason Fire Research SP Technical Research Institute of Sweden Borås Sweden Anders Lönnermark Fire Research SP Technical Research Institute of Sweden Borås Sweden Ying Zhen Li Fire Research SP Technical Research Institute of Sweden Borås Sweden ISBN 978-1-4939-2198-0 ISBN 978-1-4939-2199-7 (ebook) DOI 10.1007/978-1-4939-2199-7 Springer New York Heidelberg Dordrecht London Library of Congress Control Number: 2014954828 Springer Science+Business Media New York 2015 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. Exempted from this legal reservation are brief excerpts in connection with reviews or scholarly analysis or material supplied specifically for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. Duplication of this publication or parts thereof is permitted only under the provisions of the Copyright Law of the Publisher s location, in its current version, and permission for use must always be obtained from Springer. Permissions for use may be obtained through RightsLink at the Copyright Clearance Center. Violations are liable to prosecution under the respective Copyright Law. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. While the advice and information in this book are believed to be true and accurate at the date of publication, neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may be made. The publisher makes no warranty, express or implied, with respect to the material contained herein. Printed on acid-free paper Springer New York is a brand of Springer Springer is part of Springer Science+Business Media (www.springer.com)

Preface Fire safety engineering in tunnels is essential in order to obtain good safety for tunnel users. The knowledge about fire safety in tunnels has increased over the past few decades due to both new research and analysis of real accidents. The aim of this book is to give researchers, engineers, and authorities worldwide a good insight into the fire phenomena in tunnels and the physics behind it. Guidance in calculation of important parameters such as heat release rates, critical velocity, spread of smoke gases and heat, temperatures, heat fluxes, fire spread, and flame lengths is given as well as the theories behind them. A comprehensive overview of how fires in vehicles develop and how different physical parameters such as flammability, ventilation, and geometry influence them is presented. The focus is not on the design aspects of fire safety in tunnels, although some parts are described. It is more about understanding the dynamics and developments of fires in tunnels and other underground constructions. The tunnels are becoming more and more complex and the need for performance based design increases. The authors have found the need for presenting and gathering the latest knowledge on fire research and experience from different testing. Therefore, the emphasis is on engineering relations and physics of fires. This will provide good and solid background information which the readers can on their own hand, use in its daily research and engineering work. The knowledge presented here comes very much from research that the authors have been involved in, but also from other large-scale experiments and practical experience. The book can also serve as a base for a university education for those who are interested to understand the basics of tunnel fire safety engineering using correlations and formulas obtained within different fields. The book is divided into numerous chapters where the focus ranges from direct physical phenomena to advanced calculation models. The catastrophic fires that have occurred in tunnels are put into context of the subject of this book, namely fire dynamics in tunnels. These fires have raised the level of awareness about the problem and through experimental and theoretical work by many researchers around the world the knowledge level on the fire physics has increased v

vi Preface considerably. This knowledge needs to find its way to the engineers working with the problems on daily basis and, therefore, it is our hope that the book will serve as a platform for practicing engineers, researchers, and students dealing with fire safety in tunnels. Borås 2014-07-06 Haukur Ingason Ying Zhen Li Anders Lönnermark

Acknowledgement We would like to thank Dr Margaret McNamee, Dr Francine Amon and Dr David Lange at SP Fire Research for their valuable comments. The research presented in this book would not have been possible without financial support from SP Tunnel and Underground Safety Center. We also want to thank other Swedish research colleagues for their contribution and financial support through research projects from the Swedish Fire Research Board (BRANDFORSK), the Swedish Research Council (FORMAS), the Swedish Civil Contingencies Agency (MSB), and the Swedish Transport Administration (Trafikverket). Finally, we would like to thank the technicians at SP Fire Research who so skilfully carried out all the high quality large-scale and model-scale experimental work together with us. vii

Contents 1 Introduction... 1 1.1 Introduction... 1 1.2 Characteristics of Tunnel Fires... 2 1.3 Mitigation Systems in Tunnels... 6 1.4 Incidents in Tunnel... 9 1.4.1 Fires in Road Tunnels... 9 1.4.2 Fires in Rail Tunnels... 17 1.4.3 Fires in Metro Tunnels... 19 1.5 Summary... 20 References... 20 2 Fuel and Ventilation Controlled Fires... 23 2.1 Introduction... 23 2.2 Fire Development in Building Fires... 23 2.3 Fire Development in Tunnel Fires... 25 2.4 Fuel or Ventilation Control in a Compartment Fire... 29 2.5 Fuel or Ventilation Control in a Tunnel with Longitudinal Flow... 33 2.5.1 Fuel Control... 34 2.5.2 Ventilation Control... 35 2.5.3 Determination of Combustion Mode... 35 2.6 Effects of Vitiation on the Combustion Process... 40 2.7 Summary... 41 References... 42 3 Tunnel Fire Tests... 45 3.1 Introduction... 45 3.2 Overview of Large-Scale Tunnel Experiments... 46 3.3 Large-Scale Tunnel Fire Tests... 52 3.3.1 Ofenegg 1965... 52 3.3.2 Glasgow 1970... 55 3.3.3 The West Meon Tests in Early 1970s... 56 3.3.4 Zwenberg 1975... 56 ix

x Contents 3.3.5 P.W.R.I 1980... 61 3.3.6 TUB-VTT Tests 1986... 64 3.3.7 EUREKA EU499 Tests 1990 1992... 65 3.3.8 Memorial Tunnel Tests 1993 1995... 68 3.3.9 Shimizu No. 3 2001... 71 3.3.10 2nd Benelux Tests 2002... 72 3.3.11 Runehamar 2003... 76 3.3.12 METRO Tests 2011... 78 3.3.13 Carleton University Laboratory Train Tests 2011... 80 3.3.14 Singapore Tests 2011... 81 3.3.15 Runehamar Test 2013... 81 3.4 Model Scale Fire Tests... 81 3.4.1 The TNO Tests... 82 3.4.2 Automatic Water Spray System Tests... 82 3.4.3 Longitudinal Ventilation Tests... 82 3.4.4 Point Extraction Ventilation Tests... 83 3.4.5 Tunnel Cross-Section Tests... 83 3.5 Summary... 83 References... 84 4 Heat Release Rates in Tunnels... 89 4.1 Introduction... 89 4.2 Measured HRR in Different Vehicles... 90 4.2.1 Road Vehicles... 90 4.2.2 Railway Rolling Stock... 112 4.3 Parameters Influencing the HRR... 112 4.3.1 Heat Feedback... 112 4.3.2 Effects of Tunnel Geometry... 117 4.3.3 Effects of Ventilation on Peak HRR... 117 4.3.4 Fuel-Controlled Fires... 119 4.3.5 Ventilation-Controlled Fires... 121 4.4 HRR per Exposed Fuel Surface Area... 123 4.4.1 Liquids... 125 4.4.2 Solid Materials... 126 4.4.3 Vehicle Fires... 127 4.5 Summary... 129 References... 130 5 Fire Growth Rates in Tunnels... 135 5.1 Introduction... 135 5.2 Theory of Fire Growth Rate... 138 5.2.1 Opposed Flow Spread (Upstream)... 139 5.2.2 Wind-Aided Spread (Downstream)... 140 5.2.3 Relationship Between FGR and Flame Spread Rate... 141 5.2.4 Fuels Consisting of Several Parts... 142 5.3 Correlations for Fire Growth Rate... 143

Contents xi 5.3.1 Comparison with Model Scale Tests... 144 5.3.2 Comparison with Full Scale Tests... 145 5.4 The Effects of Windbreaks on Fire Growth Rates... 147 5.5 Summary... 149 References... 150 6 Design Fire Curves... 153 6.1 Introduction... 153 6.2 Design Fire Methods... 155 6.2.1 Constant Values for Design Fires... 155 6.2.2 Time Dependent Methods for Design Fires... 158 6.3 Exponential Design Fire Curve Method with Superposition... 162 6.3.1 Determination of Design Fire Scenarios... 163 6.3.2 Maximum Heat Release Rate... 164 6.3.3 Time to Maximum Heat Release Rate... 166 6.3.4 Energy Content... 167 6.3.5 Reconstruction of a Large Scale Test... 167 6.3.6 Design Fire for a Tram Carriage... 168 6.3.7 Design Fire for a Road Vehicle... 170 6.4 New Concept for Design Curves... 171 6.4.1 Theoretical Aspects... 172 6.4.2 Calculation... 173 6.5 Summary... 175 References... 176 7 Combustion Products from Fires... 179 7.1 Introduction... 179 7.2 Combustion and Fire Chemistry... 180 7.3 Yields... 183 7.4 Emissions from Fires in Vehicles and Tunnels... 186 7.5 Effect of Ventilation Condition... 193 7.6 Summary... 203 References... 204 8 Gas Temperatures... 207 8.1 Introduction... 207 8.2 Interaction of Ventilation Flow with Fire Plume... 209 8.3 Maximum Ceiling Gas Temperature... 211 8.3.1 Fire Plume Mass Flow Rate in a Ventilated Flow... 211 8.3.2 Maximum Ceiling Gas Temperature in a Small Fire... 213 8.3.3 Maximum Ceiling Gas Temperature in a Large Fire... 214 8.4 Position of Maximum Ceiling Gas Temperature... 219 8.5 Ceiling Gas Temperature Distribution... 222 8.6 One-Dimensional Simple Model... 227 8.7 Summary... 229 References... 230

xii Contents 9 Flame Length... 233 9.1 Introduction... 233 9.2 Overview of Flame Length in Open and Enclosure Fires... 234 9.3 Overview of Flame Length in Tunnel Fires... 236 9.4 Flame Lengths in Tunnel Fires... 237 9.4.1 Transition Between Low and High Ventilation Rate... 237 9.4.2 Model of Flame Length in Tunnel Fires... 239 9.4.3 Flame Length with High Ventilation Rate... 241 9.4.4 Flame Length Under Low Ventilation Rate... 243 9.5 Summary... 246 References... 247 10 Heat Flux and Thermal Resistance... 249 10.1 Introduction... 249 10.2 Convective Heat Transfer... 250 10.2.1 Boundary Layer... 251 10.2.2 Reynolds Colburn Analogy... 252 10.2.3 Forced Convection... 254 10.2.4 Natural Convection... 256 10.2.5 Gas Properties... 256 10.3 Radiative Heat Transfer... 257 10.3.1 Simplification in Engineering Application... 258 10.3.2 View Factor... 258 10.3.3 Radiation Among Multiple Surfaces... 259 10.3.4 Absorbing, Emitting and Scattering Gas... 260 10.4 Heat Conduction... 263 10.4.1 Thermally Thin Materials... 264 10.4.2 Thermally Thick Materials... 265 10.5 Thermal Resistance... 269 10.6 Heat Flux Measurement... 270 10.7 Calculation of Heat Fluxes in Tunnel Fires... 271 10.7.1 Exposed Tunnel Ceiling and Walls at Upper Layer... 272 10.7.2 Heat Flux in Lower Layer... 273 10.7.3 Flame Radiation in Small Tunnel Fires... 283 10.8 Summary... 288 References... 289 11 Fire Spread... 291 11.1 Introduction... 291 11.2 Introduction to the Theory of Ignition... 292 11.2.1 Solids... 292 11.2.2 Liquids... 299 11.3 Fire Spread in Tunnels... 305 11.4 Modeling of Fire Spread... 312 11.5 Summary... 317 References... 317

Contents xiii 12 Smoke Stratification... 321 12.1 Introduction... 321 12.2 Phenomenon of Smoke Stratification... 322 12.3 Mechanism of Smoke Stratification... 324 12.3.1 Entrainment... 325 12.3.2 Smoke Layer Height... 327 12.4 Simple Model of Smoke Stratification in Tunnels... 328 12.5 Summary... 331 References... 332 13 Tunnel Fire Ventilation... 333 13.1 Introduction... 333 13.2 Normal Ventilation... 334 13.2.1 Longitudinal Ventilation... 334 13.2.2 Transverse Ventilation... 336 13.2.3 Semi-transverse Ventilation... 337 13.3 Longitudinal Fire Ventilation... 337 13.3.1 Critical Velocity... 338 13.3.2 Back-Layering Length... 347 13.4 Smoke Extraction... 349 13.4.1 Single Point Extraction Volume... 351 13.4.2 Two Point Extraction... 352 13.4.3 Short Summary... 353 13.5 Cross-Passages... 354 13.6 Rescue Station... 357 13.6.1 Configuration and Function of Rescue Station... 357 13.6.2 Smoke Control... 360 13.6.3 Gas Temperature Beside the Door... 361 13.6.4 Fireproof Door Height... 362 13.7 A Simple Model of Longitudinal Flows... 362 13.8 Summary... 367 References... 368 14 Visibility... 371 14.1 Introduction... 371 14.2 Different Methods of Predicting Visibility... 372 14.3 The Influence of Visibility on Egress... 379 14.4 Summary... 383 References... 383 15 Tenability... 385 15.1 Introduction... 385 15.2 Combustion Products Related to Toxicity... 386 15.3 Toxicity... 387 15.3.1 Asphyxiants... 387 15.3.2 Irritants... 388

xiv Contents 15.4 Fractional Effective Dose, FED... 389 15.5 Fractional Effective Dose for Incapacitation... 392 15.6 Large-Scale Example of Fraction of an Incapacitation Dose... 396 15.7 Irritant Gas Model... 398 15.8 Acceptance Criteria... 399 15.9 Summary... 401 References... 401 16 Fire Suppression and Detection in Tunnels... 403 16.1 Introduction... 403 16.2 Basic Concepts of Fire Suppression Systems... 407 16.2.1 Deluge Water Spray System... 408 16.2.2 Water Mist Systems... 412 16.2.3 Foam Systems... 413 16.2.4 Mode of Operation... 414 16.3 Tunnel Fire Suppression Tests... 415 16.3.1 Second Benelux 2000 2001... 415 16.3.2 IF Tunnel, UPTUN 2002 2004... 419 16.3.3 IF Tunnel, Marioff, 2004... 419 16.3.4 VSH Hagerbach, Marioff, 2005... 420 16.3.5 San Pedro de Anes tests, Marioff, 2006... 420 16.3.6 SINTEF Runehamar Tunnel 2007... 422 16.3.7 SOLIT 2008 and SOLIT2 2012... 422 16.3.8 Singapore tests 2011 2012... 423 16.3.9 SP Runehamar Tunnel Fire Suppression Tests 2013... 424 16.3.10 A Short Discussion... 424 16.4 Theory of Fire Suppression... 425 16.4.1 Extinguishment Mechanism... 425 16.4.2 Critical Conditions for Extinction... 427 16.4.3 Fire Suppression... 431 16.4.4 A Short Discussion... 436 16.5 Tunnel Fire Detection... 436 16.5.1 Types of Fire Detection... 436 16.5.2 Summary of Fire Detection Tests in Tunnels... 438 16.5.3 A Short Discussion... 440 16.6 Summary... 441 References... 441 17 CFD Modeling of Tunnel Fires... 445 17.1 Introduction... 445 17.2 CFD Basics... 446 17.2.1 Controlling Equations... 446 17.2.2 Equation of state... 448 17.2.3 Turbulence... 449 17.2.4 Discretization Methods... 455

Contents xv 17.2.5 Solution Algorithms... 458 17.3 Sub-Models Related to Tunnel Fires... 458 17.3.1 Gas Phase Combustion... 458 17.3.2 Condensed Phase Pyrolysis... 460 17.3.3 Fire Suppression... 461 17.3.4 Wall Function... 463 17.3.5 Heat Transfer... 464 17.4 Recommendations for CFD Users... 467 17.4.1 Computation Domain and Boundary Conditions... 467 17.4.2 Fire Source... 467 17.4.3 Grid Size... 468 17.4.4 Verification of Modeling... 469 17.5 Limitations of CFD Modeling... 469 17.6 Summary... 470 References... 471 18 Scaling Technique... 473 18.1 Introduction... 473 18.2 Methods of Obtaining Scaling Correlations... 475 18.3 Classification of Scaling Techniques... 475 18.3.1 Froude Scaling... 475 18.3.2 Pressure Scaling... 475 18.3.3 Analog Scaling (Cold Gas, Saltwater)... 476 18.4 General Froude Scaling... 477 18.5 Scaling of Heat Fluxes... 480 18.5.1 Scaling of Convective Heat Transfer... 480 18.5.2 Scaling of Radiative Heat Transfer... 482 18.5.3 Scaling of Heat Conduction... 485 18.5.4 Scaling of Heat Balance in an Enclosure... 488 18.6 Scaling of Water Sprays... 491 18.6.1 Single Droplet... 491 18.6.2 Water Sprays... 493 18.6.3 Radiation Absorbed by Water Sprays... 495 18.6.4 Droplet Diameter... 496 18.6.5 Surface Cooling... 496 18.6.6 Automatic Sprinkler... 497 18.7 Scaling of Combustible Materials... 498 18.8 An Example of Scaling Application in Fire Safety Engineering... 499 18.9 Summary... 502 References... 502