2Principles of Fire Behaviorto people and property.But the study of fire to understand and to improvehumankindislimited.Itisacomplexareainvolvingmanydisciplines,anditisarelativelyprimitivefield compared toother technological areas.Yet,overthepast50years,steadyprogresshasbeenmadein itssubjects.Thisbookisa by-product of those studies.It is important to understand the history of fire science research toappreciate its contribution to the science. Equally important,it is essentialto appreciate theforces that drive such studies.The impact on people andpropertyduetofirefromrecenthistoryand frompast historyis adriverforlearning.This chapter will tryto present some of this information.Of signif-icance todayis an increasing recognition in formal academic studythat fire,as a subject discipline, is important. Today, fire is being studied at numer-ous universities around the world. The United States has two postgraduateuniversityprograms, while there are several in the United Kingdom, twoin Sweden, several in Japan,and more than a dozen in China. In fact, theChinese People's Armed Police Academy (university)outside of Beijing hasabout7000 students withmost studying fire regulations,firefighting,orfireinvestigation.Someoftheirfacultytranslated my advancedbook on fireintoChinese:詹姆士G.昆棣瑞著=Fundamentalsoffirephenomena/JamesGQuintiere;杜建科，王平；JamesG.Quintiere;JiankeDu;PingWang;YapingGao Publisher:化学工,Beijing:Hua xuegong yechuban she,2010.Indeed, thefirst edition of the current book has been translated intoKoreanand Japanese. Its interest has been primarily from the nonengineeringcommunitiesrelatedtofirefighterandfireinvestigatoreducation.Itspurposewastoattempttotranslatetheresearchdevelopmentsintodigestibleknowl-edge for these fields.It is couched in terms of descriptions of dissectedaspects offiregrowth.In addition,it includes formulas that allow predictiveestimates for these phenomena. In short, it is designed to bring tools fromresearchto the practitioner.As afirefighteryouneed toreacttofirewith reasonandknowledge,not justtrainingand instinct.Asa fireinvestigatoryouneed to supportyouropinionwithknowledge and analyses to within a scientificdegree of certainty.In this chapter, the reader is introduced to the subject of fire with its manyfeatures.What is it?Where does it come from?Howdoes it impact us? Howdid itsresearch evolve?How canwe usethatknowledge?In subsequentchapters, specificaspects of fireare addressed.What isthetemperature ofa flame? Why does flashover occur in a room fire? How does ventilationaffect thefire? We will answer these questions and more by knowledge fromresearch and formulas that allow quantitativeestimates.When this informa-tion is pieced together, you might explain what you saw in a fire or why itoccurred, or you mightdefend what youthink happened.Now let us start at the beginning
2 Principles of Fire Behavior to people and property. But the study of fire to understand and to improve humankind is limited. It is a complex area involving many disciplines, and it is a relatively primitive field compared to other technological areas. Yet, over the past 50 years, steady progress has been made in its subjects. This book is a by-product of those studies. It is important to understand the history of fire science research to appreciate its contribution to the science. Equally important, it is essential to appreciate the forces that drive such studies. The impact on people and property due to fire from recent history and from past history is a driver for learning. This chapter will try to present some of this information. Of significance today is an increasing recognition in formal academic study that fire, as a subject discipline, is important. Today, fire is being studied at numerous universities around the world. The United States has two postgraduate university programs, while there are several in the United Kingdom, two in Sweden, several in Japan, and more than a dozen in China. In fact, the Chinese People’s Armed Police Academy (university) outside of Beijing has about 7000 students with most studying fire regulations, firefighting, or fire investigation. Some of their faculty translated my advanced book on fire into Chinese: 詹姆士 G. 昆棣瑞著 = Fundamentals of fire phenomena/James G. Quintiere; 杜建科, 王平,.; James G. Quintiere; Jianke Du; Ping Wang; Yaping Gao Publisher: 化学工, Beijing: Hua xue gong ye chu ban she, 2010. Indeed, the first edition of the current book has been translated into Korean and Japanese. Its interest has been primarily from the nonengineering communities related to firefighter and fire investigator education. Its purpose was to attempt to translate the research developments into digestible knowledge for these fields. It is couched in terms of descriptions of dissected aspects of fire growth. In addition, it includes formulas that allow predictive estimates for these phenomena. In short, it is designed to bring tools from research to the practitioner. As a firefighter you need to react to fire with reason and knowledge, not just training and instinct. As a fire investigator you need to support your opinion with knowledge and analyses to within a scientific degree of certainty. In this chapter, the reader is introduced to the subject of fire with its many features. What is it? Where does it come from? How does it impact us? How did its research evolve? How can we use that knowledge? In subsequent chapters, specific aspects of fire are addressed. What is the temperature of a flame? Why does flashover occur in a room fire? How does ventilation affect the fire? We will answer these questions and more by knowledge from research and formulas that allow quantitative estimates. When this information is pieced together, you might explain what you saw in a fire or why it occurred, or you might defend what you think happened. Now let us start at the beginning
3EvolutionofFireScience1.2WhatIsFire?To understand fire, we must have a scientific definition of fire consistentwith our perceptions.In scientific terms, fire or combustion is a chemi-cal reaction involvingfuel andan oxidizer-typically,theoxygen(O,)inthe air. But this definition is insufficient, as rusting and the yellowing ofold newsprintfit this definition and they are notfire.Thedistinctiontobe fire or combustion is that significant energy has to be released. Canwe distinguish combustion from fire? Of course we cannot. In scientificterms,combustionandfirearesynonymous.Inconventionalterms,wegenerallytreatfire as distinctfrom combustion, in that fire is combustionthat is not controlled. Firefighters attempt to control it by adding wateror other agents, but theprocess of fire is not"designed"combustion, asin a furnace or an engine.Combustion experts who study such systemsmayknowverylittleaboutfire,andthosewhodeal withfiremayknowverylittleaboutallaspectsofcombustion.Theuncontrollednatureoffiremakesitdistinct.Fire is a chemical reaction that involves the evolution of light and energyin sufficient amounts to beperceptible.Generally,that energy will emitlight. The color associated with fire might be blue from formative chem-ical emittersinaflameoryellowtoredfromlightemittedbysootinaflame or smoldering char. Will there always be light in a flame (fire)? No.For instance, the burning of hydrogen (H) with air or oxygen producesonly water vapor from its chemical reaction.Although significant energyis produced, we would not visibly see flame. But in most other chemicalreactions,wewould seethecombustionprocessintermsof lightemissionfrom gases orparticulates.Afire or a flame would be energetic enough tobe sensed, particularly with sufficient energy to damage our skin. It maynotbeverybig,but its chemical energy release rate (per unit volume)wouldbe sufficient to give us a local burn injury. This is an operational definitionof fire.Fire is a chemical reaction of significant energy release with damag-ing ability.It need notbe onlya flame, as a surface reaction on solid can fitthis definition.It is the result of striking a match, the glow of the charcoalbriquettein yourgrill,the conflagration of theforest, and the spontaneitytoignition ofalargehaystack.Fireiscombustion,and combustionisachemi-cal reaction of significant energy release to cause damage. Operationally,sufficient damage can be assessed as harm to human tissue or irreversibledamagetomaterials.One last word on this chemical reaction called fire.On Earth,ittypicallyand naturally involves hydrocarbon-based fuels:those composed of atomsof carbon (C), hydrogen (H), and perhaps some oxygen (O) and nitrogen(N). Man-made materials have been added to this array of fuels (molecules),with the addition of chlorine (Cl), bromine (Br), fluorine (F), and otheratoms.For example,woodmoleculesconsistoftheatomsinvolvingH,C
Evolution of Fire Science 3 1.2 What Is Fire? To understand fire, we must have a scientific definition of fire consistent with our perceptions. In scientific terms, fire or combustion is a chemical reaction involving fuel and an oxidizer—typically, the oxygen (O2) in the air. But this definition is insufficient, as rusting and the yellowing of old newsprint fit this definition and they are not fire. The distinction to be fire or combustion is that significant energy has to be released. Can we distinguish combustion from fire? Of course we cannot. In scientific terms, combustion and fire are synonymous. In conventional terms, we generally treat fire as distinct from combustion, in that fire is combustion that is not controlled. Firefighters attempt to control it by adding water or other agents, but the process of fire is not “designed” combustion, as in a furnace or an engine. Combustion experts who study such systems may know very little about fire, and those who deal with fire may know very little about all aspects of combustion. The uncontrolled nature of fire makes it distinct. Fire is a chemical reaction that involves the evolution of light and energy in sufficient amounts to be perceptible. Generally, that energy will emit light. The color associated with fire might be blue from formative chemical emitters in a flame or yellow to red from light emitted by soot in a flame or smoldering char. Will there always be light in a flame (fire)? No. For instance, the burning of hydrogen (H2) with air or oxygen produces only water vapor from its chemical reaction. Although significant energy is produced, we would not visibly see flame. But in most other chemical reactions, we would see the combustion process in terms of light emission from gases or particulates. A fire or a flame would be energetic enough to be sensed, particularly with sufficient energy to damage our skin. It may not be very big, but its chemical energy release rate (per unit volume) would be sufficient to give us a local burn injury. This is an operational definition of fire. Fire is a chemical reaction of significant energy release with damaging ability. It need not be only a flame, as a surface reaction on solid can fit this definition. It is the result of striking a match, the glow of the charcoal briquette in your grill, the conflagration of the forest, and the spontaneity to ignition of a large haystack. Fire is combustion, and combustion is a chemical reaction of significant energy release to cause damage. Operationally, sufficient damage can be assessed as harm to human tissue or irreversible damage to materials. One last word on this chemical reaction called fire. On Earth, it typically and naturally involves hydrocarbon-based fuels: those composed of atoms of carbon (C), hydrogen (H), and perhaps some oxygen (O) and nitrogen (N). Man-made materials have been added to this array of fuels (molecules), with the addition of chlorine (Cl), bromine (Br), fluorine (F), and other atoms. For example, wood molecules consist of the atoms involving H, C
4PrinciplesofFireBehaviorandO;polyvinyl chloride(aplastic)containsH,C,andOplus Clatoms;andpolyurethane (another plastic) contains H, C, and O plus N atoms. TheseadditionstotheH-C-Obasecomplicatethenatureof combustionproductsand theirpotential threatto the environment.It is likelythat other elements,even without the addition of oxygen, could meet our combustion. In short,fire or combustion is simply a chemical reaction that can suddenly occur torelease significant energy with a relatively high temperature.Allchemical reactions conservemass,whichmeans all theatoms survive.Incontrast,inanuclearreaction someatomsareconverted intonewatomswith somematter transformed to energy.In a chemical reaction, whileatomsaremaintained,moleculesarenotconserved.Theirdestructionistheessenceofa chemical reaction.A chemical reaction converts thereactingmoleculesintonewmolecules (generally called products).Forcombustion orafire,theformationof newmolecules from the fuel and oxygen moleculesgives offa distinctamount of energy.This energy comes frombreaking thebindingforces thatheld the original molecules together.Thisisascloseaswegetinourdiscussiontomolecularphysics.Fromhereon, our discussion of fire principally concerns what we can see and feel. Ofcoursewerelyonsomemeasurements, buttheseareatthemacroscopiclevelincontrasttothemicroscopicormolecularlevel.Moreimportantly,wecometo rely on predictive formulae,for the processes, and effects of fire.Thesepredictive results come from macroscopic measurements and analyses, aswewill seeintheforthcomingchapters.1.3 Natural CausesofFireBefore humans encountered and generated fire, fire was present in theuniverse. Natural high-temperature phenomena that can cause fire are light-ning and molten rock from volcanic activity. In addition, the energy releasefromahigh-velocity impactfrom space can result in fire.Thesephenomenadate back to the formation of the Earth.As organic matter developed, wecould expect to havefire.Even today,thesephenomenaarepotential causesof accidental fire, especially lightning.1.3.1LightningWorkers keeping watch over our forests record lightning strikes. Thesestrikes can cause smoldering to the underbrush on the forest floor. A dayor twoafterthe storm,flames can erupt.Theforest crews track thesestrikesand attempt to follow up with needed extinguishment. Lightning is evenknown to cause house fires.The temperatures ina lightning bolt range toseveral thousand of degrees,and it has enormous energy
4 Principles of Fire Behavior and O; polyvinyl chloride (a plastic) contains H, C, and O plus Cl atoms; and polyurethane (another plastic) contains H, C, and O plus N atoms. These additions to the H─C─O base complicate the nature of combustion products and their potential threat to the environment. It is likely that other elements, even without the addition of oxygen, could meet our combustion. In short, fire or combustion is simply a chemical reaction that can suddenly occur to release significant energy with a relatively high temperature. All chemical reactions conserve mass, which means all the atoms survive. In contrast, in a nuclear reaction some atoms are converted into new atoms with some matter transformed to energy. In a chemical reaction, while atoms are maintained, molecules are not conserved. Their destruction is the essence of a chemical reaction. A chemical reaction converts the reacting molecules into new molecules (generally called products). For combustion or a fire, the formation of new molecules from the fuel and oxygen molecules gives off a distinct amount of energy. This energy comes from breaking the binding forces that held the original molecules together. This is as close as we get in our discussion to molecular physics. From here on, our discussion of fire principally concerns what we can see and feel. Of course we rely on some measurements, but these are at the macroscopic level in contrast to the microscopic or molecular level. More importantly, we come to rely on predictive formulae, for the processes, and effects of fire. These predictive results come from macroscopic measurements and analyses, as we will see in the forthcoming chapters. 1.3 Natural Causes of Fire Before humans encountered and generated fire, fire was present in the universe. Natural high-temperature phenomena that can cause fire are lightning and molten rock from volcanic activity. In addition, the energy release from a high-velocity impact from space can result in fire. These phenomena date back to the formation of the Earth. As organic matter developed, we could expect to have fire. Even today, these phenomena are potential causes of accidental fire, especially lightning. 1.3.1 Lightning Workers keeping watch over our forests record lightning strikes. These strikes can cause smoldering to the underbrush on the forest floor. A day or two after the storm, flames can erupt. The forest crews track these strikes and attempt to follow up with needed extinguishment. Lightning is even known to cause house fires. The temperatures in a lightning bolt range to several thousand of degrees, and it has enormous energy
5Evolutionof Fire Science1.3.2EarthquakeOfmoreconcerntomodernsocietyistheeffectofanearthquake.Whilethereisnodirectfirefromanearthquake,thedisturbanceofcombustiondevicesand fuel sources provides the means to initiate fire.An earthquake can playhavocwithfire and fuel sourcesused forheating and cooking.Indeed,insome earthquake events, the resulting fire has caused more damagethantheground shock.ThiswastruefortheconflagrationsresultingfromtheSanFranciscoearthquakeof1906andtheGreatKantoearthquakeof1923in Tokyo and Yokohama.During the fire following the Kanto earthquake38,000 people were killed by a fire whirl-a flaming tornado-that spunoff the mainfire column.This unusual phenomenon was likely caused bywinds from a nearby typhoon.People that had taken refuge in a park adja-centto theSumida Riverinthe Hifukusho-ato districtof Tokyowere directlyimpactedbythislargefirewhirl.This horrorisdepicted inthe JapaneseprintinFigure1.la and inthegruesomephotographof corpsesresultingfromthefirewhirl inFigure1.1b.Atotalof143,000peopleoverallarereportedtohaveperishedintheKantoearthquakeandfire.ManyrefertotheSanFranciscoearthquakeof 1906as theGreatFireofSanFrancisco.1Thefire, caused bybrokengaslines and disturbedgas andoildevices, burned for 74 hours after the quake.It burned over 4.7 square milesdestroying28,000buildings.Sevenhundredwerereportedtohavedied,butthis could be as high as four times this number. The death toll estimate is联修火风旋大面方町橱横新本上福底(a)FIGURE1.1(a) Japanese painting of the Kanto earthquake fire whirl (1923) from Y. Hasemi.(Continued)
Evolution of Fire Science 5 1.3.2 Earthquake Of more concern to modern society is the effect of an earthquake. While there is no direct fire from an earthquake, the disturbance of combustion devices and fuel sources provides the means to initiate fire. An earthquake can play havoc with fire and fuel sources used for heating and cooking. Indeed, in some earthquake events, the resulting fire has caused more damage than the ground shock. This was true for the conflagrations resulting from the San Francisco earthquake of 1906 and the Great Kanto earthquake of 1923 in Tokyo and Yokohama. During the fire following the Kanto earthquake, 38,000 people were killed by a fire whirl—a flaming tornado—that spun off the main fire column. This unusual phenomenon was likely caused by winds from a nearby typhoon. People that had taken refuge in a park adjacent to the Sumida River in the Hifukusho-ato district of Tokyo were directly impacted by this large fire whirl. This horror is depicted in the Japanese print in Figure 1.1a and in the gruesome photograph of corpses resulting from the fire whirl in Figure 1.1b. A total of 143,000 people overall are reported to have perished in the Kanto earthquake and fire. Many refer to the San Francisco earthquake of 1906 as the Great Fire of San Francisco.1 The fire, caused by broken gas lines and disturbed gas and oil devices, burned for 74 hours after the quake. It burned over 4.7 square miles destroying 28,000 buildings. Seven hundred were reported to have died, but this could be as high as four times this number. The death toll estimate is (a) FIGURE 1.1 (a) Japanese painting of the Kanto earthquake fire whirl (1923) from Y. Hasemi. (Continued)
Principles of Fire Behavior113·114上下6饿版扇路记第心心机大充亡者，衣期性氧流记の滋谈o6a依torL2tt88(b)FIGURE1.1(Continued)(b) Photograph of corpses killed by the fire whirl in Hifukusho-ato, Tokyo (1923) from K. Saito.not firm,and some place it ashigh as 6000.Firefightinghad limited wateravailable.Itwasbroughtunder controlbythe useof dynamiting.iIncontrastthe Loma Prieta earthquakeof 1989 in San Franciscokilled 63 and causeda fire in the Marina district that destroyed four buildings.Firefighters hadtroublegettingwatertothefireduetobrokenwatermains.More recently, earthquakes in Japan produced differing fire damage.AroundKobe(January17,1995)theGreatHanshinEarthquake,in which6400died,severalfireconflagrationsoccurred.Thefiresdestroyed over6000buildings. In contrast, in March 2011, the Tohoku earthquake and tsunamidid not result in significant fires. However, the effects of the event on the
6 Principles of Fire Behavior not firm, and some place it as high as 6000. Firefighting had limited water available. It was brought under control by the use of dynamiting.1 In contrast, the Loma Prieta earthquake of 1989 in San Francisco killed 63 and caused a fire in the Marina district that destroyed four buildings. Firefighters had trouble getting water to the fire due to broken water mains. More recently, earthquakes in Japan produced differing fire damage. Around Kobe (January 17, 1995) the Great Hanshin Earthquake, in which 6400 died, several fire conflagrations occurred. The fires destroyed over 6000 buildings. In contrast, in March 2011, the Tohoku earthquake and tsunami did not result in significant fires. However, the effects of the event on the (b) FIGURE 1.1 (Continued) (b) Photograph of corpses killed by the fire whirl in Hifukusho-ato, Tokyo (1923) from K. Saito