AcknowledgmentsThe author and Delmar Publishers would like to thank the following reviewers for the com-ments and suggestions they offered during the development of this project. Our gratitude isextended to:Edward M.Garrison, CFIClint SmokeATFNorthern Virginia Community CollegeRaleigh, NCAnnandale,VAChris HawleyRobert LafordBaltimore CountyFire DepartmentMassachusettsFirefightingAcademyTowson,MDOrangeFireDepartmentOrange,MADavid L.FultzLSUFiremanTraining ProgramMichael McKennaBaton Rouge, LAMissionCollegeSanta Clara,CATom HarmerTitusvilleFire&EmergencyServicesTimothy G.PittsTitusville,FLGuilfordTechnical CommunityCollegeGreensboroFireDepartmentJackFennerUniversity of CincinnatiGreensboro,NCCincinnati,OHRodWesterfieldTraining HorizonsJohnMirochaSouthernStoneCountyFireProtectionSenior Special AgentDistrictBureau of Alcohol,Tobacco,andKimberling City,MOFirearmsChicago, ILTheodoreK.CashelFire MarshalPrinceton TownshipPrinceton,NJxi
Acknowledg1nents The author and Delmar Publishers would like to thank the following reviewers for the comments and suggestions they offered during the development of this project. Our gratitude is extended to: Edward M. Garrison, CFI ATF Raleigh, NC Robert Laford Massachusetts Firefighting Academy Orange Fire Department Orange, MA Michael McKenna Mission College Santa Clara, CA Timothy G. Pitts Guilford Technical Community College Greensboro Fire Department Greensboro, NC Rod Westerfield Training Horizons Southern Stone County Fire Protection District Kimberling City, MO Theodore K. Cashel Fire Marshal Princeton Township Princeton, NJ xi Clint Smoke Northern Virginia Community College Annandale, VA Chris Hawley Baltimore County Fire Department Towson .MD David L. Fultz LSU Fireman Training Program Baton Rouge, LA Tom Harmer Titusville Fire & Emergency Services Titusville, FL Jack Fenner University of Cincinnati Cincinnati, OH John Mirocha Senior Special Agent Bureau of Alcohol, Tobacco, and Firearms Chicago, IL
ChapterThe Evolution ofFire ScienceLearning ObjectivesUpon completionofthischapter,youshouldbeableto:Definefire.Develop an awareness of fire in history.Understand thefactorsmotivatingfireresearch.Recognize the role of visualization and scale models in fire researchExplainS.I.unitsandscientificsymbols
The Evolution ot= ll=ire Science Upon completion of this chapter, you should be able to: ■ Define fire. ■ Develop an awareness of fire in history. ■ Understand the factors motivating fire research. ■ Recognize the role of visualization and scale models in fire research. ■ Explain S. I. units and scientific symbols. 1
Chapter1TheEvolution of FireScienceINTRODUCTIONTo understand fire, we must have a scientific definition of fire consistent with ourperceptions. We must understand the role fire has played in history-its benefitsand its costs to society in terms of people and property damage.Controlled fire,or combustion,for useful power is studied in conjunction with the market forcesthat drive our economy.The study of uncontrolled fire appears tobe motivated byclear risks to society and by societies having the means to invest in such study.Thedevelopment of the science of fire has accelerated over the last 150 years.It is acomplex area involvingmanydisciplines,and it is relativelyprimitive comparedtoothertechnological fields.WHATIS FIRE?fireBefore there was life there was fire. It has left its imprint on history in many ways.anuncontrolledIn scientificterms,fireor combustion is a chemicalreaction involving fuel and anchemical reactionoxidizertypically the oxygen (O,) in the air. Rusting and the yellowing of oldproducing light andnewsprintdofit this definition; however,thoseprocesses are neither combustionenergysufficienttonorfirefor energy mustbe released forthereto be either.Can we distinguish com-damage the skinbustionfromfire?In scientific terms,combustionand fireare synonymous.In con-ventionalterms,wegenerallytreatfireasdistinctfrom combustion,inthatfireiscombustioncombustion that is not intended to be controlled.Firefighters attempt to control itfire,orcontrolledfireby adding water or other agents, but the process of fire is not"designed" com-bustion,asinafurnaceoran engine.Combustionexpertswhostudysuch systemsmayknow very little about fire,and those who deal with fire mayknow very lit-tle about combustion.Fire is a chemical reaction that involves the evolution of light and energy insufficient amounts to be perceptible. Will there always be light in a flame (fire)?No.For instance,theburning of hydrogen (H2)with air or oxygen produces onlywater vaporfrom its chemical reaction.Although significant energy is produced,we would notsee flame.But in most other fire classificationswe would see thecombustion process and a fire or a flame would be energetic enough to be sensed,particularly with sufficient energy to damage our skin.It may notbe very big, butits energyreleaserate per unit volume of the chemical reaction zone would be sufficient to give us a local burn injury.This is fire.It is the result of striking a match,the glow of the charcoal briquette, the conflagration of theforest,and the spon-taneityofasmokinghaystack.One last word on this chemical reaction called fire:On Earth it typicallyinvolveshydrocarbon-based fuels,those composed ofatoms of carbon (C).hydro-gen (H), and perhaps some oxygen (O) and nitrogen (N). Man-made substanceshave been added to this array of materials (molecules), such as chlorine (Cl)bromine (Br),fluorine (F)and other atoms.For example,wood molecules consist
-~-c_h_ap_t_er_1_Th_e_Ev_o_1u_ti_on_o_f_F_ir_e_sc_ie_nc_e fire an uncontrolled chemical reaction producing light and energy sufficient to damage the skin combustion fire, or controlled fire INTR0DUOI0N To understand fire, we must have a scientific definition of fire consistent with our perceptions. We must understand the role fire has played in history-its benefits and its costs to society in terms of people and property damage. Controlled fire, or combustion, for useful power is studied in conjunction with the market forces that drive our economy. The study of uncontrolled fire appears to be motivated by clear risks to society and by societies having the means to invest in such study. The development of the science of fire has accelerated over the last 150 years. It is a complex area involving many disciplines, and it is relatively primitive compared to other technological fields. WHAT IS FIRE? Before there was life there was fire. It has left its imprint on history in many ways. In scientific terms, fire or combustion is a chemical reaction involving fuel and an oxidizer-typically the oxygen (0 2) in the air. Rusting and the yellowing of old newsprint do fit this definition; however, those processes are neither combustion nor fire for energy must be released for there to be either. Can we distinguish combustion from fire? 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 intended to be 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 combustion. Fire is a chemical reaction that involves the evolution of light and energy in sufficient amounts to be perceptible. 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 see flame. But in most other fire classifications we would see the combustion process and 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 energy release rate per unit volume of the chemical reaction zone would be sufficient to give us a local burn injury. This is fire. It is the result of striking a match, the glow of the charcoal briquette, the conflagration of the forest, and the spontaneity of a smoking haystack. One last word on this chemical reaction called fire: On Earth it typically involves hydrocarbon-based fuels, those composed of atoms of carbon (C), hydrogen (H), and perhaps some oxygen (0) and nitrogen (N). Man-made substances have been added to this array of materials (molecules), such as chlorine (Cl), bromine (Br), fluorine (F) and other atoms. For example, wood molecules consist
Chapter1TheEvolution of FireScienceoftheatoms involvingH,C,and;polyvinyl chloride(plastic)containsH,C,andNOTEO plus Cl atoms; and polyurethane (plastic) contains H,C,and Oplus Natoms.A chemical reactionThese additions to the H-C-Obase complicate the nature of combustion productsdestroys molecules butand their potential threatto the environment.notatoms.All chemical reactions conservemass,which means all the atoms survive,incontrast toa nuclear reaction in which some atoms are converted into new atomswith some matter transformed to energy.In a chemical reaction,however, mole-cules are not conserved.Their destruction is the essence of a chemical reaction inwhich they are converted to new molecules.For combustion or a fire, the forma-tionofnewmoleculesfromthefuelandoxygenmoleculesgivesoffanetamountof energy.This energy comes from releasing the binding forces that hold the mol-ecules together.This is as close as we get to molecular physics.From here on,our discussionoffireprincipallyconcernswhat we canseeand feel.Ofcoursewerelyon somemeasurements, but these are at the macroscopic level in contrast to the micro-scopicormolecularlevel.NATURALCAUSESOFFIRENatural phenomena that can cause fire because of their high temperatures arelightning and molten rock from volcanic activity.Thesephenomena datebackto theformation of the Earth.As organicmatter developed,we could expect tohave fire.Even today,these phenomena are a leading cause of accidental fire.Lightning strikes are recorded by the workers keeping watch over our forests.These strikes can cause smoldering underbrush on theforest floor, and a day ortwo after a storm, flames can erupt.The forest crews track these strikes andattempt tofollow upwith needed extinguishment.Of more concern tomodernsociety is the effect of an earthquake,rather than direct volcanic activity.Anearthquake can play havoc with fire and fuel sources used for heating and cook-ing.More damage was done by the conflagrations resulting from the San Francisco earthquake of 1906 and the Great Kanto earthquake of 1923 in Tokyo andYokohama than from the actual quakes.During the fire following the Kantoearthquake,38,o00 people werekilled by a fire whirl-a flaming tornado-thatspun off the mainfire column.Thesepeoplehad taken refuge in a park adjacentto the Sumida river in the Hitukuso-Ato district of Tokyo.This horror is depict-ed intheJapaneseprintinFigure1-1a andinthegruesomephotographofcorpses resulting from the fire whirl in Figure 1-ib.It is surprising thatmorestudy is not done on the effects of fire due to earthquake as opposed to the struc-tural impactofthe jolt.There is one more natural cause of fire that humankind has not experienced,but unfortunately,the dinosaurs did.It has been generally established that inabout65millionB.C.alargemeteoritesmashedintotheEarth,Themeteorite'spas
Chapter 1 The Evolution of Fire Science ■ NOTE A chemical reaction destroys molecules but not atoms. of the atoms involving H, C, and O; polyvinyl chloride (plastic) contains H, C, and 0 plus Cl atoms; and polyurethane (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. All chemical reactions conserve mass, which means all the atoms survive, in contrast to a nuclear reaction in which some atoms are converted into new atoms with some matter transformed to energy. In a chemical reaction, however, molecules are not conserved. Their destruction is the essence of a chemical reaction in which they are converted to new molecules. For combustion or a fire, the formation of new molecules from the fuel and oxygen molecules gives off a net amount of energy. This energy comes from releasing the binding forces that hold the molecules together. This is as close as we get 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. NATURAL CAUSES OF FIRE Natural phenomena that can cause fire because of their high temperatures are lightning and molten rock from volcanic activity. 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 a leading cause of accidental fire. Lightning strikes are recorded by the workers keeping watch over our forests. These strikes can cause smoldering underbrush on the forest floor, and a day or two after a storm, flames can erupt. The forest crews track these strikes and attempt to follow up with needed extinguishment. Of more concern to modern society is the effect of an earthquake, rather than direct volcanic activity. An earthquake can play havoc with fire and fuel sources used for heating and cooking. More damage was done by the conflagrations resulting from the San Francisco earthquake of 1906 and the Great Kanto earthquake of 1923 in Tokyo and Yokohama than from the actual quakes. 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. These people had taken refuge in a park adjacent to the Sumida river in the Hitukuso-Ato district of Tokyo. This horror is depicted in the Japanese print in Figure 1-la and in the gruesome photograph of corpses resulting from the fire whirl in Figure 1-lb. It is surprising that more study is not done on the effects of fire due to earthquake as opposed to the structural impact of the jolt. There is one more natural cause of fire that humankind has not experienced, but unfortunately, the dinosaurs did. It has been generally established that in about 65 million B.C. a large meteorite smashed into the Earth. The meteorite's pas-
Chapter1The Evolution of Fire ScienceFigure1-1aJapanesepaintingofthefirewhirl during thegreatKantoearthquakeinTokyo,1923.Photocourtesy of Y.Hasemi.Figure1-1bPhotograph ofcorpsesfromtheeffectof the firewhirl intheHitukuso-Atodistrict of Tokyo,1923.PhotocourtesyofK.Saito
Figure 1-1a Japanese painting of the fire whirl during the great Kanta earthquake in Tokyo, 1923.Photo courtesy of Y. Hasemi. Figure Mb Photograph of corpses from the effect of the fire whirl in the Hitukuso-Ato district of Tokyo, 1923. Photo courtesy of K. Saito. Chapter 1 The Evolution of Fire Science