Tunnel Fire Dynamics

Transcription

1 Tunnel Fire Dynamics

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

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 ISBN (ebook) DOI / Springer New York Heidelberg Dordrecht London Library of Congress Control Number: 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 (

4 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

5 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 Haukur Ingason Ying Zhen Li Anders Lönnermark

6 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

7 Contents 1 Introduction Introduction Characteristics of Tunnel Fires Mitigation Systems in Tunnels Incidents in Tunnel Fires in Road Tunnels Fires in Rail Tunnels Fires in Metro Tunnels Summary References Fuel and Ventilation Controlled Fires Introduction Fire Development in Building Fires Fire Development in Tunnel Fires Fuel or Ventilation Control in a Compartment Fire Fuel or Ventilation Control in a Tunnel with Longitudinal Flow Fuel Control Ventilation Control Determination of Combustion Mode Effects of Vitiation on the Combustion Process Summary References Tunnel Fire Tests Introduction Overview of Large-Scale Tunnel Experiments Large-Scale Tunnel Fire Tests Ofenegg Glasgow The West Meon Tests in Early 1970s Zwenberg ix

8 x Contents P.W.R.I TUB-VTT Tests EUREKA EU499 Tests Memorial Tunnel Tests Shimizu No nd Benelux Tests Runehamar METRO Tests Carleton University Laboratory Train Tests Singapore Tests Runehamar Test Model Scale Fire Tests The TNO Tests Automatic Water Spray System Tests Longitudinal Ventilation Tests Point Extraction Ventilation Tests Tunnel Cross-Section Tests Summary References Heat Release Rates in Tunnels Introduction Measured HRR in Different Vehicles Road Vehicles Railway Rolling Stock Parameters Influencing the HRR Heat Feedback Effects of Tunnel Geometry Effects of Ventilation on Peak HRR Fuel-Controlled Fires Ventilation-Controlled Fires HRR per Exposed Fuel Surface Area Liquids Solid Materials Vehicle Fires Summary References Fire Growth Rates in Tunnels Introduction Theory of Fire Growth Rate Opposed Flow Spread (Upstream) Wind-Aided Spread (Downstream) Relationship Between FGR and Flame Spread Rate Fuels Consisting of Several Parts Correlations for Fire Growth Rate

9 Contents xi Comparison with Model Scale Tests Comparison with Full Scale Tests The Effects of Windbreaks on Fire Growth Rates Summary References Design Fire Curves Introduction Design Fire Methods Constant Values for Design Fires Time Dependent Methods for Design Fires Exponential Design Fire Curve Method with Superposition Determination of Design Fire Scenarios Maximum Heat Release Rate Time to Maximum Heat Release Rate Energy Content Reconstruction of a Large Scale Test Design Fire for a Tram Carriage Design Fire for a Road Vehicle New Concept for Design Curves Theoretical Aspects Calculation Summary References Combustion Products from Fires Introduction Combustion and Fire Chemistry Yields Emissions from Fires in Vehicles and Tunnels Effect of Ventilation Condition Summary References Gas Temperatures Introduction Interaction of Ventilation Flow with Fire Plume Maximum Ceiling Gas Temperature Fire Plume Mass Flow Rate in a Ventilated Flow Maximum Ceiling Gas Temperature in a Small Fire Maximum Ceiling Gas Temperature in a Large Fire Position of Maximum Ceiling Gas Temperature Ceiling Gas Temperature Distribution One-Dimensional Simple Model Summary References

10 xii Contents 9 Flame Length Introduction Overview of Flame Length in Open and Enclosure Fires Overview of Flame Length in Tunnel Fires Flame Lengths in Tunnel Fires Transition Between Low and High Ventilation Rate Model of Flame Length in Tunnel Fires Flame Length with High Ventilation Rate Flame Length Under Low Ventilation Rate Summary References Heat Flux and Thermal Resistance Introduction Convective Heat Transfer Boundary Layer Reynolds Colburn Analogy Forced Convection Natural Convection Gas Properties Radiative Heat Transfer Simplification in Engineering Application View Factor Radiation Among Multiple Surfaces Absorbing, Emitting and Scattering Gas Heat Conduction Thermally Thin Materials Thermally Thick Materials Thermal Resistance Heat Flux Measurement Calculation of Heat Fluxes in Tunnel Fires Exposed Tunnel Ceiling and Walls at Upper Layer Heat Flux in Lower Layer Flame Radiation in Small Tunnel Fires Summary References Fire Spread Introduction Introduction to the Theory of Ignition Solids Liquids Fire Spread in Tunnels Modeling of Fire Spread Summary References

11 Contents xiii 12 Smoke Stratification Introduction Phenomenon of Smoke Stratification Mechanism of Smoke Stratification Entrainment Smoke Layer Height Simple Model of Smoke Stratification in Tunnels Summary References Tunnel Fire Ventilation Introduction Normal Ventilation Longitudinal Ventilation Transverse Ventilation Semi-transverse Ventilation Longitudinal Fire Ventilation Critical Velocity Back-Layering Length Smoke Extraction Single Point Extraction Volume Two Point Extraction Short Summary Cross-Passages Rescue Station Configuration and Function of Rescue Station Smoke Control Gas Temperature Beside the Door Fireproof Door Height A Simple Model of Longitudinal Flows Summary References Visibility Introduction Different Methods of Predicting Visibility The Influence of Visibility on Egress Summary References Tenability Introduction Combustion Products Related to Toxicity Toxicity Asphyxiants Irritants

12 xiv Contents 15.4 Fractional Effective Dose, FED Fractional Effective Dose for Incapacitation Large-Scale Example of Fraction of an Incapacitation Dose Irritant Gas Model Acceptance Criteria Summary References Fire Suppression and Detection in Tunnels Introduction Basic Concepts of Fire Suppression Systems Deluge Water Spray System Water Mist Systems Foam Systems Mode of Operation Tunnel Fire Suppression Tests Second Benelux IF Tunnel, UPTUN IF Tunnel, Marioff, VSH Hagerbach, Marioff, San Pedro de Anes tests, Marioff, SINTEF Runehamar Tunnel SOLIT 2008 and SOLIT Singapore tests SP Runehamar Tunnel Fire Suppression Tests A Short Discussion Theory of Fire Suppression Extinguishment Mechanism Critical Conditions for Extinction Fire Suppression A Short Discussion Tunnel Fire Detection Types of Fire Detection Summary of Fire Detection Tests in Tunnels A Short Discussion Summary References CFD Modeling of Tunnel Fires Introduction CFD Basics Controlling Equations Equation of state Turbulence Discretization Methods

13 Contents xv Solution Algorithms Sub-Models Related to Tunnel Fires Gas Phase Combustion Condensed Phase Pyrolysis Fire Suppression Wall Function Heat Transfer Recommendations for CFD Users Computation Domain and Boundary Conditions Fire Source Grid Size Verification of Modeling Limitations of CFD Modeling Summary References Scaling Technique Introduction Methods of Obtaining Scaling Correlations Classification of Scaling Techniques Froude Scaling Pressure Scaling Analog Scaling (Cold Gas, Saltwater) General Froude Scaling Scaling of Heat Fluxes Scaling of Convective Heat Transfer Scaling of Radiative Heat Transfer Scaling of Heat Conduction Scaling of Heat Balance in an Enclosure Scaling of Water Sprays Single Droplet Water Sprays Radiation Absorbed by Water Sprays Droplet Diameter Surface Cooling Automatic Sprinkler Scaling of Combustible Materials An Example of Scaling Application in Fire Safety Engineering Summary References