Fire Behavior & Combustion
Author(s): Michael McKenna
Edition: 1
Copyright: 2022
Edition: 2
Copyright: 2024
Edition: 2
Copyright: 2024
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The audience for the book is primarily members of the fire service studying fire as part of a degree program, as well as anyone wanting to study fire. The intent of the book is to provide a depth of knowledge in fi re behavior, so hopefully, to provide just a bit of fire behavior information that will help firefighters make more informed decisions. It is also intended to provide enough science and extra physics, so hopefully, as the National Institute for Standards and Technology and the Fire Safety Research Institute continue to study fire, understanding the information will come more naturally to the firefighter. The book is aimed as a bridge between the oversimplistic studies of fire behavior and the full-on calculus-based, deep physics textbooks. I leave mathematical calculations intentionally out of the book but put many formulas into the book to help understand the relationships between values. I attempted to leave openings where the instructor could use the text as a launching point to go into more complicated directions if they choose. I am not a scientist but have learned the value of science and mathematics by studying fire behavior. With the exception of my time in the Safety Division, I spent my entire career riding a fire engine, putting “wet stuff on the red stuff.” The book contains many case studies because I believe it is best to intertwine real events with the study of fire behavior. Unfortunately, all the case studies have one thing in common, and that is line of duty death. Fire behavior makes every fireground a dynamic and dangerous place that can be very unpredictable. What seems completely benign can become deadly in moments. I am not talking about minutes or even seconds. Sometimes tragedy happens in an instant. Case studies provide real-life fire behavior situations. It is important to note that the event in a case study does not necessarily correspond to the chapter topic. I felt that was too limiting, and there are many important circumstances to study. These fires are presented with the mindset of fire behavior, and I made no judgments or comments on any fireground actions. The presentations are about the fire behavior. This book is not perfect, and I am always open to feedback. In the process of simplification of some of the principles, I may have lost something in the translation. Hopefully, the book leads to a better understanding of the science behind fire behavior and helps forge a better understanding of fire.
Introduction
Preface
Cancer
Acknowledgements
About the author
Fire and Emergency Services Higher Learning (FESHE) Matrix
Chapter 1 Introduction to Fire
1 Introduction
1.1 The Modern Study of Fire
1.2 National Institute of Standards and Technology (NIST)
1.3 UL Fire Safety Research Institute (FRSI)
1.4 Mathematics in Fire Behavior
1.4.1 Standard International (SI) system
1.4.2 Scientific Notation
1.4.3 Temperature Measurement
1.5 Mathematics of Change
1.5.1 Inverse Relationships
1.5.2 Rise over Run
Chapter 2 Science of Fire
2 Introduction
2.1 Fire and Combustion
2.1.1 The Basics of Fire
2.2 Definition of Fire
2.3 Heat Movement
2.4 Fire Triangle – The Initiation of Fire
2.5 Fire Tetrahedron
2.6 States of Energy
2.6.1 Potential Energy
2.6.2 Kinetic Energy
2.7 Law of Conservation of Energy
2.8 States of Matter
2.8.1 Gas Molecules
2.8.1.1 Ideal Gas Law
2.8.2 Liquids
2.8.3 Solids
Chapter 3 Forms of Fire
3 Introduction
3.1 Heat Transfer Within the Reaction Zone
3.1.1 Second Law of Thermodynamics
3.2 Fuel Vapor Movement Within the Reaction Zone
3.2.1 Fick’s Law of Diffusion
3.2.2 Graham’s Law of Diffusion
3.3 Trilogy of Energy Transfer
3.4 Pyrolysis
3.5 Heat of Gasification
3.6 Fire Zone
3.7 Forms of Fire
3.7.1 Diffusion Flames
3.7.1.1 Laminar Diffusion Flame
3.7.1.2 Turbulent Diffusion Flame
3.7.2 Smoldering
3.7.3 Spontaneous Combustion
3.7.3.1 One Meridian Plaza
3.7.4 Premixed Flames
3.7.4.1 Flash Point
3.7.4.2 Fire Point
3.7.4.3 Auto-Ignition Temperature
Chapter 4 Conduction and Convection
4 Introduction
4.1 Heat Versus Temperature
4.2 Conduction
4.2.1 Fourier’s Law of Conduction
4.2.2 Specific Heat
4.2.3 Thermal Diffusivity
4.2.4 Thermal Penetration Time
4.3 Convection
4.3.1 Convective Heat Transfer Coefficient
4.4 Energy Loss
Chapter 5 Radiation
5 Introduction
5.1 Radiant Heat as Driving Force
5.2 Heat Flux
5.2.1 Stephan-Boltzmann Constant
5.3 Emissivity
5.4 Radiant Heat Transfer Model
5.5 Protection from Radiant Heat
Chapter 6 Ignition
6 Introduction
6.1 Types of Ignitions
6.2 Ignition of Liquids
6.3 Ignition of Solids
6.3.1 Surface to Mass Ratio
6.3.2 Net Heat Flux
6.3.3 Heat Flow Through a Solid
6.3.3.1 Steady Flow
6.3.3.2 Unsteady Flow
6.4 Fire Spread
6.5 Flame Spread
6.6 Flame Spread on Solid Surfaces
Chapter 7 Heat Release Rate
7 Introduction
7.1 Heat Release Rate
7.2 Traditional Heat Release Rate Curve
7.3 Legacy Versus Modern Fire Growth Curves
7.3.1 Modern Fire Growth Curve
7.3.2 t2 Fire Growth Curves
Chapter 8 Fire Plumes and Flow Path
8 Introduction
8.1 Fire Plumes
8.2 Mathematical Shape of the Fire Plume
8.3 Buoyancy
8.4 Entrained Air
8.4.1 Flame Height
8.5 Laminar Flow
8.6 Ceiling Jet
8.7 Flow Path
Chapter 9 Compartment Fires
9 Introduction
9.1 Compartment Fire
9.1.1 Stages of a Compartment Fire
9.2 Fire Growth Timeline
9.3 Ventilation
9.4 Developing Fire
9.5 Two-Zone Model
9.6 Energy Balance
Chapter 10 Compartment Fire Dynamics
10 Introduction
10.1 Rollover
10.2 Flashover
10.2.1 Elements of the Flashover
10.2.2 Conditions Required for a Flashover
10.2.3 Flashover Sequence of Events
10.2.4 Flashover Variables
10.3 Backdraft
10.3.1 Backdraft Sequence
10.3.2 Indicators of a Backdraft
Chapter 11 Extinguishment
11 Introduction
11.1 Classes of Fire
11.2 Interruption of the Process
11.3 Water
11.3.1 Latent Heat of Vaporization
11.3.2 Water Flow Calculations
11.4 Foam
11.4.1 Class A foam
11.4.2 Class B foam
11.5 Dry Extinguishment
11.6 Department of Transportation hazard classification system
Chapter 12 Smoke and Products of Combustion
12 Introduction
12.1 Characteristics of Smoke
12.1.1 Volume
12.1.2 Velocity
12.1.3 Density
12.1.4 Color
12.2 Toxicity of Smoke
12.2.1 Carbon Monoxide
12.2.2 Hydrogen Cyanide
12.3 Toxicity and the Untenable Environment
Chapter 13 Fire models
13 Introduction
13.1 Fire Modeling Applications
13.2 Notable NIST FDS Simulations
13.3 Zone Models
13.4 Computational fluid dynamics models (Field models)
References
Michael McKenna retired after almost 32 years of professional fire service experience, including more than 19 years as a fire captain and more than seven years as a fire district safety officer. Captain McKenna is an alumnus of the International Association of Firefighters. Captain McKenna has been instructing Fire Technology, specializing in quantitative Fire Behavior, since 1999. Captain McKenna has over 21 years of fire service program management and problem-solving and solution development. He has been involved with the NFPA fire service consensus standards development since 1988 and sits as a principal member of NFPA 1950, NFPA 1851, NFPA 1930, and the Correlating Committee on Fire and Emergency Services Protective Clothing and Equipment. Captain McKenna has published many articles on firefighter issues. As a principal in Captain McKenna & Associates, LLC, he works with fire departments and other organizations on issues of firefighter safety and solutions design. He has lectured around the United States and Latin America on fire service issues, including fi re behavior. Captain McKenna is a subject matter expert on firefighter burn injuries, line-of-duty death, and near-misses and, as such, has worked as a Managing Technical Advisor to the National Institute of Occupational Safety and Health at the National Personal Protection Laboratory in Morgantown, West Virginia. In addition, Captain McKenna provides expert testimony and trial consulting in matters of firefighter injury or death. Michael McKenna has a Bachelor of Arts degree in Economics & Public Policy development from California State University Sacramento and an Associate of Arts degree in Fire Technology from American River College.
The audience for the book is primarily members of the fire service studying fire as part of a degree program, as well as anyone wanting to study fire. The intent of the book is to provide a depth of knowledge in fi re behavior, so hopefully, to provide just a bit of fire behavior information that will help firefighters make more informed decisions. It is also intended to provide enough science and extra physics, so hopefully, as the National Institute for Standards and Technology and the Fire Safety Research Institute continue to study fire, understanding the information will come more naturally to the firefighter. The book is aimed as a bridge between the oversimplistic studies of fire behavior and the full-on calculus-based, deep physics textbooks. I leave mathematical calculations intentionally out of the book but put many formulas into the book to help understand the relationships between values. I attempted to leave openings where the instructor could use the text as a launching point to go into more complicated directions if they choose. I am not a scientist but have learned the value of science and mathematics by studying fire behavior. With the exception of my time in the Safety Division, I spent my entire career riding a fire engine, putting “wet stuff on the red stuff.” The book contains many case studies because I believe it is best to intertwine real events with the study of fire behavior. Unfortunately, all the case studies have one thing in common, and that is line of duty death. Fire behavior makes every fireground a dynamic and dangerous place that can be very unpredictable. What seems completely benign can become deadly in moments. I am not talking about minutes or even seconds. Sometimes tragedy happens in an instant. Case studies provide real-life fire behavior situations. It is important to note that the event in a case study does not necessarily correspond to the chapter topic. I felt that was too limiting, and there are many important circumstances to study. These fires are presented with the mindset of fire behavior, and I made no judgments or comments on any fireground actions. The presentations are about the fire behavior. This book is not perfect, and I am always open to feedback. In the process of simplification of some of the principles, I may have lost something in the translation. Hopefully, the book leads to a better understanding of the science behind fire behavior and helps forge a better understanding of fire.
Introduction
Preface
Cancer
Acknowledgements
About the author
Fire and Emergency Services Higher Learning (FESHE) Matrix
Chapter 1 Introduction to Fire
1 Introduction
1.1 The Modern Study of Fire
1.2 National Institute of Standards and Technology (NIST)
1.3 UL Fire Safety Research Institute (FRSI)
1.4 Mathematics in Fire Behavior
1.4.1 Standard International (SI) system
1.4.2 Scientific Notation
1.4.3 Temperature Measurement
1.5 Mathematics of Change
1.5.1 Inverse Relationships
1.5.2 Rise over Run
Chapter 2 Science of Fire
2 Introduction
2.1 Fire and Combustion
2.1.1 The Basics of Fire
2.2 Definition of Fire
2.3 Heat Movement
2.4 Fire Triangle – The Initiation of Fire
2.5 Fire Tetrahedron
2.6 States of Energy
2.6.1 Potential Energy
2.6.2 Kinetic Energy
2.7 Law of Conservation of Energy
2.8 States of Matter
2.8.1 Gas Molecules
2.8.1.1 Ideal Gas Law
2.8.2 Liquids
2.8.3 Solids
Chapter 3 Forms of Fire
3 Introduction
3.1 Heat Transfer Within the Reaction Zone
3.1.1 Second Law of Thermodynamics
3.2 Fuel Vapor Movement Within the Reaction Zone
3.2.1 Fick’s Law of Diffusion
3.2.2 Graham’s Law of Diffusion
3.3 Trilogy of Energy Transfer
3.4 Pyrolysis
3.5 Heat of Gasification
3.6 Fire Zone
3.7 Forms of Fire
3.7.1 Diffusion Flames
3.7.1.1 Laminar Diffusion Flame
3.7.1.2 Turbulent Diffusion Flame
3.7.2 Smoldering
3.7.3 Spontaneous Combustion
3.7.3.1 One Meridian Plaza
3.7.4 Premixed Flames
3.7.4.1 Flash Point
3.7.4.2 Fire Point
3.7.4.3 Auto-Ignition Temperature
Chapter 4 Conduction and Convection
4 Introduction
4.1 Heat Versus Temperature
4.2 Conduction
4.2.1 Fourier’s Law of Conduction
4.2.2 Specific Heat
4.2.3 Thermal Diffusivity
4.2.4 Thermal Penetration Time
4.3 Convection
4.3.1 Convective Heat Transfer Coefficient
4.4 Energy Loss
Chapter 5 Radiation
5 Introduction
5.1 Radiant Heat as Driving Force
5.2 Heat Flux
5.2.1 Stephan-Boltzmann Constant
5.3 Emissivity
5.4 Radiant Heat Transfer Model
5.5 Protection from Radiant Heat
Chapter 6 Ignition
6 Introduction
6.1 Types of Ignitions
6.2 Ignition of Liquids
6.3 Ignition of Solids
6.3.1 Surface to Mass Ratio
6.3.2 Net Heat Flux
6.3.3 Heat Flow Through a Solid
6.3.3.1 Steady Flow
6.3.3.2 Unsteady Flow
6.4 Fire Spread
6.5 Flame Spread
6.6 Flame Spread on Solid Surfaces
Chapter 7 Heat Release Rate
7 Introduction
7.1 Heat Release Rate
7.2 Traditional Heat Release Rate Curve
7.3 Legacy Versus Modern Fire Growth Curves
7.3.1 Modern Fire Growth Curve
7.3.2 t2 Fire Growth Curves
Chapter 8 Fire Plumes and Flow Path
8 Introduction
8.1 Fire Plumes
8.2 Mathematical Shape of the Fire Plume
8.3 Buoyancy
8.4 Entrained Air
8.4.1 Flame Height
8.5 Laminar Flow
8.6 Ceiling Jet
8.7 Flow Path
Chapter 9 Compartment Fires
9 Introduction
9.1 Compartment Fire
9.1.1 Stages of a Compartment Fire
9.2 Fire Growth Timeline
9.3 Ventilation
9.4 Developing Fire
9.5 Two-Zone Model
9.6 Energy Balance
Chapter 10 Compartment Fire Dynamics
10 Introduction
10.1 Rollover
10.2 Flashover
10.2.1 Elements of the Flashover
10.2.2 Conditions Required for a Flashover
10.2.3 Flashover Sequence of Events
10.2.4 Flashover Variables
10.3 Backdraft
10.3.1 Backdraft Sequence
10.3.2 Indicators of a Backdraft
Chapter 11 Extinguishment
11 Introduction
11.1 Classes of Fire
11.2 Interruption of the Process
11.3 Water
11.3.1 Latent Heat of Vaporization
11.3.2 Water Flow Calculations
11.4 Foam
11.4.1 Class A foam
11.4.2 Class B foam
11.5 Dry Extinguishment
11.6 Department of Transportation hazard classification system
Chapter 12 Smoke and Products of Combustion
12 Introduction
12.1 Characteristics of Smoke
12.1.1 Volume
12.1.2 Velocity
12.1.3 Density
12.1.4 Color
12.2 Toxicity of Smoke
12.2.1 Carbon Monoxide
12.2.2 Hydrogen Cyanide
12.3 Toxicity and the Untenable Environment
Chapter 13 Fire models
13 Introduction
13.1 Fire Modeling Applications
13.2 Notable NIST FDS Simulations
13.3 Zone Models
13.4 Computational fluid dynamics models (Field models)
References
Michael McKenna retired after almost 32 years of professional fire service experience, including more than 19 years as a fire captain and more than seven years as a fire district safety officer. Captain McKenna is an alumnus of the International Association of Firefighters. Captain McKenna has been instructing Fire Technology, specializing in quantitative Fire Behavior, since 1999. Captain McKenna has over 21 years of fire service program management and problem-solving and solution development. He has been involved with the NFPA fire service consensus standards development since 1988 and sits as a principal member of NFPA 1950, NFPA 1851, NFPA 1930, and the Correlating Committee on Fire and Emergency Services Protective Clothing and Equipment. Captain McKenna has published many articles on firefighter issues. As a principal in Captain McKenna & Associates, LLC, he works with fire departments and other organizations on issues of firefighter safety and solutions design. He has lectured around the United States and Latin America on fire service issues, including fi re behavior. Captain McKenna is a subject matter expert on firefighter burn injuries, line-of-duty death, and near-misses and, as such, has worked as a Managing Technical Advisor to the National Institute of Occupational Safety and Health at the National Personal Protection Laboratory in Morgantown, West Virginia. In addition, Captain McKenna provides expert testimony and trial consulting in matters of firefighter injury or death. Michael McKenna has a Bachelor of Arts degree in Economics & Public Policy development from California State University Sacramento and an Associate of Arts degree in Fire Technology from American River College.