17EvolutionofFireScienceThe results are not consistent, giving ambiguity to the term flammabilityPerhaps it is appropriate that in a book intended topresent accurate prose,theword flammableis listed amongthosemisused:Flammable, an oddity, chiefly useful in saving lives. The common wordmeaning"combustible" is inflammable. But some people are thrown offby the in-and think inflammable means"not combustible."For this rea-son, trucks carrying gasoline or explosives are now marked flammable.Unless you areoperating such a truck and hence are concerned withthesafety of children and illiterates, use inflammable.15This change in the word was likely done in the interest of safety, but it canstill cause confusion,especiallyif you areFrench.A clear scientificbasisisneeded to classifythefirehazard ofmaterials.We still do not currently have a universal test procedure to establish flam-mability or,alternatively,inflammability.These current testsare reflectionsof our misuse of the word. The world cannot seem to establish a universaltest.In the 1990s, Europe sought to harmonize its flammability tests.First,they considered the tests of the"Three Sisters": national tests of Germany,France, and the United Kingdom. The results gave a chart again like theEmmons graph. They were using as a benchmark the Room Corner Test.That test measures the energy release of fire spreading on a wall and ceil-ing material in a room subject to a corner ignition. That is a realistic testforliningmaterials,butitisexpensive.So,thedesireisinsteadtohaveasmall laboratoryinexpensivetestas thestandard.Theyfocused ontheConeCalorimeter as a candidate test for the standard.That test can measure thetimeto ignition and therate of energy releasedbyamaterial.This seems likeagood scientific match.Butfire standardsarepolitical,between thepride ofcountries,and theimpact on commercial products.Someplasticmaterialsdid notlook good in theConetest, and ultimately,a newtest was inventedto"bringharmony"to Europe.Thisshould notbethewayprogressismadefor fire safety.If only industry and countries would realize that a universaltestbasedonscientificmeasurementscanbeablessing.Ablessingisnot justto safetybut alsoto the cost of doing business and streamlining commerce.Even if it is not at first a perfect test, a scientific test can be built upon withfutureknowledgeand madebetter.Today,anad hoctestwithdefects is com-monlyreplaced by anotherarbitrary test.1.5.6Costof FireThe annual costs of fire are not insignificant, but because of the rela-tively low frequency of fire compared to other societal threats, theyarenot fully appreciated. Moreover, fire safety costs do not increase the pro-ductivity of the economy; they are a drag on the economy. Costs haveto be expended tomake buildingssafefrom fireand tomakeproducts
Evolution of Fire Science 17 The results are not consistent, giving ambiguity to the term flammability. Perhaps it is appropriate that in a book intended to present accurate prose, the word flammable is listed among those misused: Flammable, an oddity, chiefly useful in saving lives. The common word meaning “combustible” is inflammable. But some people are thrown off by the in- and think inflammable means “not combustible.” For this reason, trucks carrying gasoline or explosives are now marked flammable. Unless you are operating such a truck and hence are concerned with the safety of children and illiterates, use inflammable.15 This change in the word was likely done in the interest of safety, but it can still cause confusion, especially if you are French. A clear scientific basis is needed to classify the fire hazard of materials. We still do not currently have a universal test procedure to establish flammability or, alternatively, inflammability. These current tests are reflections of our misuse of the word. The world cannot seem to establish a universal test. In the 1990s, Europe sought to harmonize its flammability tests. First, they considered the tests of the “Three Sisters”: national tests of Germany, France, and the United Kingdom. The results gave a chart again like the Emmons graph. They were using as a benchmark the Room Corner Test. That test measures the energy release of fire spreading on a wall and ceiling material in a room subject to a corner ignition. That is a realistic test for lining materials, but it is expensive. So, the desire is instead to have a small laboratory inexpensive test as the standard. They focused on the Cone Calorimeter as a candidate test for the standard. That test can measure the time to ignition and the rate of energy released by a material. This seems like a good scientific match. But fire standards are political, between the pride of countries, and the impact on commercial products. Some plastic materials did not look good in the Cone test, and ultimately, a new test was invented to “bring harmony” to Europe. This should not be the way progress is made for fire safety. If only industry and countries would realize that a universal test based on scientific measurements can be a blessing. A blessing is not just to safety but also to the cost of doing business and streamlining commerce. Even if it is not at first a perfect test, a scientific test can be built upon with future knowledge and made better. Today, an ad hoc test with defects is commonly replaced by another arbitrary test. 1.5.6 Cost of Fire The annual costs of fire are not insignificant, but because of the relatively low frequency of fire compared to other societal threats, they are not fully appreciated. Moreover, fire safety costs do not increase the productivity of the economy; they are a drag on the economy. Costs have to be expended to make buildings safe from fire and to make products
18PrinciplesofFireBehaviorless likely to contribute to fire.When these costs become toogreat, moreattention will be made to minimizing them.For now they are viewed asregulatory costs that are a necessary burden tobusiness.The cost of firesafetyisa societalissue.It was estimated in 1991 that the annual cost of fire in the United Stateswas s$85 billion.16 The overall cost includes property loss, business interrup-tion,product liability, insurance administrative costs, fire service (paid),and fire protection in construction and equipment.Today,this cost is muchhigher.Table1.3shows thepercentageofmajor countryfire costs scaled totheirgross domesticproducts (GDP)for 2002-2008.The costs for theUnitedStates (2008) in actual dollars are as follows: property loss $17 billion, fireprotection in construction $62 billion, fire service $41 billion, and insuranceadministrative costs $18 billion for a total of s138billion.The cost continuesto increase, likelyduetoinflation.But as can be seen, it is typical for many developed countries to investnearly 1% of their GDP in fire-related costs.The United States appearstospend themostrelativetoGDP.Unfortunately,noteven1%or2%ofthesefirecostsareinvestedback intoimprovingourknowledgeoftheTABLE1.3NationalAnnualFireCostsbyPercentageofGDPfor2002-2008PropertyBuilding FireFire InsuranceCountryLossTotalProtectionAdministrationFirefightingNDNDNDCanadaND0.320.08NDNDNDNDSpain0.120.140.090.300.65Japan0.17ND0.030.20NDFinland0.110.410.120.270.91United States0.070.160.060.050.34Slovenia0.110.230.080.160.58NewZealand0.13ND0.04NDNDGermany0.160.31ND0.19NDNetherlands0.080.35ND0.16NDAustralia0.130.220.100.210.66United Kingdom0.170.350.05NDNDItaly0.200.090.070.62Denmark0.26Sweden0.170.190.050.130.540.200.180.07NDNDFrance0.200.360.100.110.77Norway0.050.020.030.390.49SingaporeSource:World Fire Statistics Centre Bulletin 12 &27,The Geneva Association,Geneva, Switzerland,1996/2011.ND,datanotavailable
18 Principles of Fire Behavior less likely to contribute to fire. When these costs become too great, more attention will be made to minimizing them. For now they are viewed as regulatory costs that are a necessary burden to business. The cost of fire safety is a societal issue. It was estimated in 1991 that the annual cost of fire in the United States was $85 billion.16 The overall cost includes property loss, business interruption, product liability, insurance administrative costs, fire service (paid), and fire protection in construction and equipment. Today, this cost is much higher. Table 1.3 shows the percentage of major country fire costs scaled to their gross domestic products (GDP) for 2002–2008.9 The costs for the United States (2008) in actual dollars are as follows: property loss $17 billion, fire protection in construction $62 billion, fire service $41 billion, and insurance administrative costs $18 billion for a total of $138 billion.9 The cost continues to increase, likely due to inflation. But as can be seen, it is typical for many developed countries to invest nearly 1% of their GDP in fire-related costs. The United States appears to spend the most relative to GDP. Unfortunately, not even 1% or 2% of these fire costs are invested back into improving our knowledge of the TABLE 1.3 National Annual Fire Costs by Percentage of GDP for 2002–2008 Country Property Loss Building Fire Protection Fire Insurance Administration Firefighting Total Canada ND 0.32 ND ND ND Spain 0.08 ND ND ND ND Japan 0.12 0.14 0.09 0.30 0.65 Finland 0.17 ND 0.03 0.20 ND United States 0.11 0.41 0.12 0.27 0.91 Slovenia 0.07 0.16 0.06 0.05 0.34 New Zealand 0.11 0.23 0.08 0.16 0.58 Germany 0.13 ND 0.04 ND ND Netherlands 0.16 0.31 ND 0.19 ND Australia 0.08 0.35 ND 0.16 ND United Kingdom 0.13 0.22 0.10 0.21 0.66 Italy 0.17 0.35 0.05 ND ND Denmark 0.20 0.26 0.09 0.07 0.62 Sweden 0.17 0.19 0.05 0.13 0.54 France 0.20 0.18 0.07 ND ND Norway 0.20 0.36 0.10 0.11 0.77 Singapore 0.05 0.39 0.02 0.03 0.49 Source: World Fire Statistics Centre Bulletin 12 & 27, The Geneva Association, Geneva, Switzerland, 1996/2011. ND, data not available
19Evolutionof FireSciencetechnology of fire safety.For the United States, the investment in researchis less than 0.04% of annual cost of fire todayby my estimates.Typically,industrywillinvestmorethan3%ofitsrevenueintoresearchtoimproveitsproducts.In 1975, when the most productive research period for fire researchoccurred in theUnited States, the investmentwas about 0.06%of totalfire costs.Not a big difference,buta lotmore moneyto stimulate researchand make progress was available back then. Today, this would amounttoanincreaseinresearchforfireatabouts27millionperyearormore.This is not a lot of money for society to invest, but it would make a bigdifference for fire safety.Thereare few advocates for such an increase.Lessons are not just learned from history but must also be analyzedusing the science of fire. Research is needed to lay the foundation of thefull knowledge base. Perhaps the future will bring more fire researchas fire investigators and firefighters are becoming more sensitive to itspotential benefits.Doubtless,future disasters will shape the course of fire safety.In develop-ing nations, high-rise buildings are being built to heights that dwarf currentlevels. It is possible that thousands of occupants will be seriously affectedor killed by a fire disaster in a high-rise building. The previous sentencewasinthefirsteditionpublishedbeforeSeptember11,2001.TheWTC9/11fire event is now classified as the"deadliest large loss fire"in history withover2000 deadand aloss of $41 billion (in2010 $)according toNFPA.7Sincethen therehas been the Caracas Tower fire (2004) with flames travel-ing from the 34th floor to 26 stories above; the 38-story Windsor Buildingfire in Madrid (2005) that burned for more than 24 hours; and the BeijingMandarinOrientalHotel (550fttall),unoccupied,burnedoutcompletelyin3 hours.Fortunately,loss of life was not the issue in these three buildings,but the vulnerability of tall buildings to fire is key. Fire safety in tall build-ings deserves special attention.Future living arrangements in outer space under low gravity and inunderground and undersea structures will present unexpected firehazards.Many large cities around the world are moving underground,especiallyforpeopleincommutingandforshopping.Wealreadyseetheissues with moving into the forest environment. Issues related to seekingnew forms of power will bring new problems.Electric and hydrogen-based vehicles will present new fire issues. With hydrogen it is obvious,but higher voltagebatterieswill bethe likely cause offires in the newmorecombustiblevehicles.Fireaffectingradioactiveoperations and toxicwastestorage sites will continue to present hazards of new dimensions. We havealready seen this at Fukushima.There will be new fire hazard surprisesinfuturetechnologicaladvancementsandproductsdespiteimprovementsin fire safety technologies. We are likely not to fully anticipate the firehaz-ard of newtechnologies
Evolution of Fire Science 19 technology of fire safety. For the United States, the investment in research is less than 0.04% of annual cost of fire today by my estimates. Typically, industry will invest more than 3% of its revenue into research to improve its products. In 1975, when the most productive research period for fire research occurred in the United States, the investment was about 0.06% of total fire costs. Not a big difference, but a lot more money to stimulate research and make progress was available back then. Today, this would amount to an increase in research for fire at about $27 million per year or more. This is not a lot of money for society to invest, but it would make a big difference for fire safety. There are few advocates for such an increase. Lessons are not just learned from history but must also be analyzed using the science of fire. Research is needed to lay the foundation of the full knowledge base. Perhaps the future will bring more fire research as fire investigators and firefighters are becoming more sensitive to its potential benefits. Doubtless, future disasters will shape the course of fire safety. In developing nations, high-rise buildings are being built to heights that dwarf current levels. It is possible that thousands of occupants will be seriously affected or killed by a fire disaster in a high-rise building. The previous sentence was in the first edition published before September 11, 2001. The WTC 9/11 fire event is now classified as the “deadliest large loss fire” in history with over 2000 dead and a loss of $41 billion (in 2010 $) according to NFPA.7 Since then there has been the Caracas Tower fire (2004) with flames traveling from the 34th floor to 26 stories above; the 38-story Windsor Building fire in Madrid (2005) that burned for more than 24 hours; and the Beijing Mandarin Oriental Hotel (550 ft tall), unoccupied, burned out completely in 3 hours. Fortunately, loss of life was not the issue in these three buildings, but the vulnerability of tall buildings to fire is key. Fire safety in tall buildings deserves special attention. Future living arrangements in outer space under low gravity and in underground and undersea structures will present unexpected fire hazards. Many large cities around the world are moving underground, especially for people in commuting and for shopping. We already see the issues with moving into the forest environment. Issues related to seeking new forms of power will bring new problems. Electric and hydrogenbased vehicles will present new fire issues. With hydrogen it is obvious, but higher voltage batteries will be the likely cause of fires in the new more combustible vehicles. Fire affecting radioactive operations and toxic waste storage sites will continue to present hazards of new dimensions. We have already seen this at Fukushima. There will be new fire hazard surprises in future technological advancements and products despite improvements in fire safety technologies. We are likely not to fully anticipate the fire hazard of new technologies
20PrinciplesofFireBehavior1.6FireResearchThe study of fire is a complex subject that comprises an array of interde-pendent disciplines.Each of these subjects needs to bedeveloped before thepieces canbe puttogether to adequately describefire.Science istheevolutionof many steps and contributions. Eventually, the subject takes shape, andindividuals formulate or unify the subject by quantitative description thatallows forpredictions andassessments.This processleads toa formallyrec-ognized scientificdiscipline fora subject.Let usbriefly examine thehistoryofthesecomponent subjectsthatunderliefire.1.6.1DisciplinesThatUnderlieFireFireis uncontrolled combustion involving chemistry,thermodynamicsfluid mechanics,and heat transfer.Thermodynamics,the study of energyand states of matter, was principally shaped by Willard Gibbs, a notednineteenth-century scientist, who brought unification and clarity to thesubject that is still appreciated today. Heat transfer also had its roots in theearly1800s.Joseph Fourier,a general in Napoleon's army,formulated thelawofheatconduction thatformsthe theoretical basis of thefield.But heat trans-ferin fluids had to await thedevelopment of modern fluid mechanics inthelate1800s when thepioneering work of OsborneReynolds on turbulentflow laid the basis for practical engineering analysis in fluid mechanics. Inthe 1900s, Theodore von Karman and others advanced the subjectof aero-dynamics, which paved the way for a more complete framework for heattransfer.Atthispoint,solutions werebased on approximatemethods, sincethegoverningmathematicalequationsweretoocomplextobeexactly solved.In combustion,Y.B.Zel'dovitch,aRussian scientist, was able to formulatesolutionsfor diffusion flames using innovativeapproximatemathematicaltechniques.Althoughbeguninthe1930s,thesubjectofcombustionwasnotdevelopedtoamaturestateuntilthe1950s.1.6.2ComputerSimulationsand PhysicsToday,fast and large capacity computers make it possible to approximatelysolve the basic equations with good accuracy. Many facets of combustioncan berendered by computer simulations, but issues of turbulence,chemi-cal kinetics, and other small-scale phenomena still cannot be completelyresolved by these computersolutions.Over the last decade, many more engineers and investigators of fire arenow turning to computer solutions.TheFire Dynamics Simulator, originat-ing from National Institute of Standards and Technology (NIST),presentsa graphical user-friendly tool. The code is based on the solution of the fun-damental governing equations but still must rely on underlying models
20 Principles of Fire Behavior 1.6 Fire Research The study of fire is a complex subject that comprises an array of interdependent disciplines. Each of these subjects needs to be developed before the pieces can be put together to adequately describe fire. Science is the evolution of many steps and contributions. Eventually, the subject takes shape, and individuals formulate or unify the subject by quantitative description that allows for predictions and assessments. This process leads to a formally recognized scientific discipline for a subject. Let us briefly examine the history of these component subjects that underlie fire. 1.6.1 Disciplines That Underlie Fire Fire is uncontrolled combustion involving chemistry, thermodynamics, fluid mechanics, and heat transfer. Thermodynamics, the study of energy and states of matter, was principally shaped by Willard Gibbs, a noted nineteenth-century scientist, who brought unification and clarity to the subject that is still appreciated today. Heat transfer also had its roots in the early 1800s. Joseph Fourier, a general in Napoleon’s army, formulated the law of heat conduction that forms the theoretical basis of the field. But heat transfer in fluids had to await the development of modern fluid mechanics in the late 1800s when the pioneering work of Osborne Reynolds on turbulent flow laid the basis for practical engineering analysis in fluid mechanics. In the 1900s, Theodore von Kármán and others advanced the subject of aerodynamics, which paved the way for a more complete framework for heat transfer. At this point, solutions were based on approximate methods, since the governing mathematical equations were too complex to be exactly solved. In combustion, Y.B. Zel’dovitch, a Russian scientist, was able to formulate solutions for diffusion flames using innovative approximate mathematical techniques. Although begun in the 1930s, the subject of combustion was not developed to a mature state until the 1950s. 1.6.2 Computer Simulations and Physics Today, fast and large capacity computers make it possible to approximately solve the basic equations with good accuracy. Many facets of combustion can be rendered by computer simulations, but issues of turbulence, chemical kinetics, and other small-scale phenomena still cannot be completely resolved by these computer solutions. Over the last decade, many more engineers and investigators of fire are now turning to computer solutions. The Fire Dynamics Simulator, originating from National Institute of Standards and Technology (NIST), presents a graphical user-friendly tool. The code is based on the solution of the fundamental governing equations but still must rely on underlying models
21EvolutionofFireSciencefor combustionand turbulence.FMGlobal hasembarked on an alternativecode called FireFOAM.Theseeffortsareadvancing thestateofthe art infirecomputation.There is no doubt that as computers get still bigger and faster,thesecomputersimulationswillbeinvaluable.As with all models, computer codes can be misused, as they can presentrealistic graphical renditions of fire and smoke in their output. The resultsmay look right but can bequantitatively inaccurate.Such results must alwaysbe validated for their specific application. This validation must rely onexperimental data that bring generality to the problem. Such experimentalstudies have been the backbone of engineering science. They have laid thefoundation of formulas that match the generality of the data and circumventtheneedfor fundamental mathematical solutions involving complexities ofturbulence and combustion.This book deals with thesebackbone formulas.The use of such formulas relies on understanding the subject.The engineermust rely on intellectual insight and understanding to use these approxi-mateformulations correctly.Only when a thorough understanding of a sub-jectismasteredcansimplerepresentationsofcomplexphenomenabemadeandappreciated.Theseformulaeandtheirdevelopmentformthebasisofeducationand thetransferofknowledge.Withoutthisbasis,wecan justturnon the computer and get an answer.Weneed both computer simulationsand approximateformula for specificprocesses.The intelligent useof bothapproaches is key for design and analysis. They should provide a counter-checktoeachother.1.6.3BriefHistoryofFireScienceLet us return to thehistory of fire science.The subject of fireneeded to buildonallofitscomponentdisciplines.Theseinteractionsamongthedisciplineshad tomaturebeforeitwasevenpossibletoadequatelydescribeandpredictfire.Ican remember in the1970s combustion scientists talking to behavior-ists, chemists talking to toxicologists, and firefighters talking to engineers.These discussions areneeded today to bring a balance to the science offire.Anotherfactor influencing the development of fire science is the moti-vation to study it in the first place. We can see that fire is a drain on theeconomy,and thereis no directmarket incentivefor its study.In Japan,theconsequences of earthquakes led to an extreme sensitivity to fire safety andits study.Fire science is studied in schools of architecture in Japan as well asin other scientific fields.It is endemic in Japanese culture and academic dis-ciplines.Not surprisingly,the first science-based handbook on the quantita-tive description of fire was published in Japan in the early1980s.Even todayI am amazed at the infrastructureforfire researchin Japan.At their annualscientific meetings, it is not uncommon to have up to 100 technical presen-tations on fire.Indeed, the first Society of FireProtectionEngineers (SFPE)standard issued inMay2011(SFPEEngineeringStandard onCalculatingFireExposures to Structures)is derived from Japanese research and standards
Evolution of Fire Science 21 for combustion and turbulence. FMGlobal has embarked on an alternative code called FireFOAM. These efforts are advancing the state of the art in fire computation. There is no doubt that as computers get still bigger and faster, these computer simulations will be invaluable. As with all models, computer codes can be misused, as they can present realistic graphical renditions of fire and smoke in their output. The results may look right but can be quantitatively inaccurate. Such results must always be validated for their specific application. This validation must rely on experimental data that bring generality to the problem. Such experimental studies have been the backbone of engineering science. They have laid the foundation of formulas that match the generality of the data and circumvent the need for fundamental mathematical solutions involving complexities of turbulence and combustion. This book deals with these backbone formulas. The use of such formulas relies on understanding the subject. The engineer must rely on intellectual insight and understanding to use these approximate formulations correctly. Only when a thorough understanding of a subject is mastered can simple representations of complex phenomena be made and appreciated. These formulae and their development form the basis of education and the transfer of knowledge. Without this basis, we can just turn on the computer and get an answer. We need both computer simulations and approximate formula for specific processes. The intelligent use of both approaches is key for design and analysis. They should provide a countercheck to each other. 1.6.3 Brief History of Fire Science Let us return to the history of fire science. The subject of fire needed to build on all of its component disciplines. These interactions among the disciplines had to mature before it was even possible to adequately describe and predict fire. I can remember in the 1970s combustion scientists talking to behaviorists, chemists talking to toxicologists, and firefighters talking to engineers. These discussions are needed today to bring a balance to the science of fire. Another factor influencing the development of fire science is the motivation to study it in the first place. We can see that fire is a drain on the economy, and there is no direct market incentive for its study. In Japan, the consequences of earthquakes led to an extreme sensitivity to fire safety and its study. Fire science is studied in schools of architecture in Japan as well as in other scientific fields. It is endemic in Japanese culture and academic disciplines. Not surprisingly, the first science-based handbook on the quantitative description of fire was published in Japan in the early 1980s. Even today I am amazed at the infrastructure for fire research in Japan. At their annual scientific meetings, it is not uncommon to have up to 100 technical presentations on fire. Indeed, the first Society of Fire Protection Engineers (SFPE) standard issued in May 2011 (SFPE Engineering Standard on Calculating Fire Exposures to Structures) is derived from Japanese research and standards