Cellulose spot fire ignition by hot metal particles

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Proceedings of the Combustion Institute xxx (2014) xxx–xxx

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Cellulose spot fire ignition by hot metal particles

James L. Urban ⇑, Casey D. Zak, Carlos Fernandez-Pello

Department of Mechanical Engineering, University of California, Berkeley, CA 94720, USA

Abstract

The ignition of natural combustible material by hot metal particles is an important fire ignition pathwayby which wildland and urban spot fires are started. There are numerous cases reported of wild fires startedby clashing power-lines or from sparks generated by machines or engines. Similarly there are many casesreported of industrial fires caused by grinding and welding sparks. In this work, the effect of metal type onthe ability of hot metal particles to cause flaming ignition of powdered cellulose fuel beds is studied exper-imentally. The materials studied are stainless steel, aluminum, brass and copper. These metals are repre-sentative of clashing conductors (aluminum and copper) and those involved in machine friction and hotwork such as welding (stainless steel and brass). Cellulose powder is used as a surrogate for natural fuelbeds. Particles of various sizes from 2 to 11 mm in diameter are heated to various temperatures between575 and 1100 � C and dropped onto the fuel bed. The results show a hyperbolic relationship betweenparticle size and temperature, with the larger particles requiring lower temperatures to ignite the cellulosethan the smaller particles. For large particles of all the metals, the ignition boundary is not very sensitive toparticle size. For small particles the ignition boundaries are similar for the different metals and sensitive toboth energy and temperature. The thermal properties of the metal play a lesser role in determining ignitionwith exception of the energy release from melting when it occurs. It also appears that the controlling igni-tion mechanisms by large particles are different than those from the small particles. The former appears tobe determined primarily by the particle surface temperature while the later by the particle energy andtemperature.� 2014 Published by Elsevier Inc. on behalf of The Combustion Institute.

Keywords: Ignition; Wildland fires; Natural fuels; Solid phase combustion

1. Introduction

The ignition of natural combustible materialby hot metal particles is an important fire ignitionpathway by which wildland and urban spot firesare started. There have been many fires whichhave been allegedly caused by hot metal particles

http://dx.doi.org/10.1016/j.proci.2014.05.0811540-7489/� 2014 Published by Elsevier Inc. on behalf of The

⇑ Corresponding author. Fax: +1 510 642 1850.E-mail address: [email protected] (J.L. Urban).

Please cite this article in press as: J.L. Urban et al.10.1016/j.proci.2014.05.081

and sparks landing in a combustible solid mate-rial. There are some references which have com-piled lists of such fires [1–12], but many remainunreferenced because they have been involved inlitigation. According to published data [13,14],powerlines, equipment, and railroads causedapproximately 28,000 natural fuel fires annuallyin the United States. Some of these fires were cat-astrophic with extensive damage to land, propertyand lives. As an example, the Witch Creek andGuejito fires burned almost 200,000 acres and

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Fig. 1. Schematic of experimental apparatus.

2 J.L. Urban et al. / Proceedings of the Combustion Institute xxx (2014) xxx–xxx

destroyed over 1100 homes during the 2007 Cali-fornia firestorm. According to reports by TheCalifornia Department of Forestry and FireProtection (CalFire) and NIST, both fire wereallegedly started by hot metal particles generatedby power lines [2,3]. Another recent large wild-land/urban fire is the Bastrop County Complexwildfire in Texas; it burned 12,787 hectares in2011. The fire allegedly started when powerlinesinteracted with each other and nearby trees duringhigh winds. The resulting sparks ignited driedgrass and vegetation [4]. Similar fires haveoccurred in many other countries. In New Zea-land 275 fires were ignited by embers, sparks orflying brands between 2005 and 2010 [5]. In Aus-tralia, some of the wild fires of the Black Saturdayevent of February 2009 were also allegedly gener-ated by sparks and propagated extremely fast byember spotting [7,8]. Particles and sparks pro-duced by welding, grinding and various forms ofhot work have also been involved in several othernotable incidents, and the established literaturediscusses many potential particle sources [9–12].

There are a limited number of studies pub-lished on the ignition of fuel beds by hot metalparticles [15–19]. The first published work, byRowntree and Stokes, [15], studied the ignitionpotential of barley grass by aluminum particles.Tanaka [16], studied the ignition of sawdust bywelding spatter. Work conducted at the labora-tory of the present authors by Hadden et al. [17]studied the potential of stainless steel particles tosmolder or flaming ignite powdered cellulose beds.Zak et al. [18] studied the ignition of powderedcellulose by contact with stainless steel and brassparticles while also varying the moisture contentof the cellulose fuel beds. They later developed astatistical treatment of similar data [19].

In this study, the authors’ previous work onthe subject is consolidated and extended to thestudy of the ignition by metals that melt at rela-tively low temperatures. A large number ofignition tests were conducted to accurately deter-mine and compare the flaming ignition limits offour relevant metals. These metals are representa-tive of clashing conductors (aluminum and cop-per) and of particles produced by machinefriction and hot work such as welding (stainlesssteel and brass). The addition of low melting tem-perature materials, specifically aluminum, to thisstudy and the comparison of their ignition behav-ior with that of high melting temperature metalshelps in the determination of the role of the parti-cles energy on the fuel ignition process. Whileboth flaming and smoldering ignition are impor-tant potential causes of spot fires, this workfocuses on flaming ignition. It should be pointedout, however, that smoldering ignition requiresless stringent conditions than flaming ignition[17]; thus, the results of this work are in thisregard limited. The initiation of self-supported


smoldering fronts and their associated transitionto flaming due to varying cross flow wind speedare sufficiently complex as to deserve their ownseries of investigations.

The ignition of a porous solid fuel bed by a hotmetal particle is very complex. Once the hot parti-cle lands on the fuel bed its energy is transferred tothe fuel and surrounding ambient surroundings. Ifthe particle has enough energy the fuel near theparticle is heated and pyrolyzes, while the particlecools down. The pyrolyzate mixes with the air anda flammable gaseous mixture may be generatednear the particle. If the particle is still hot enoughit can act as a pilot and ignite the gaseous mixture.If it is not hot enough to act as a pilot it still canprovide enough energy to initiate the ignition ofthe gas by a spontaneous ignition process. Alter-natively the hot metal particle can initiate a selfsustained smolder of the fuel that eventuallymay transition into flaming. Thus, this complexignition process depends on several factors,including the size and state of the particle (temper-ature, molten, oxidizing), the characteristics of thefuel bed on which it lands (temperature, density,porosity, moisture content), the characteristics ofthe particle landing (fully or partially embeddedon the fuel bed, bouncing, splashing) and environ-mental conditions (temperature, humidity, windvelocity). Obviously a study of this complexitymust be parameterized. In this work, we have lim-ited the variables to the particle size, temperatureand metal type. All the other parameters havebeen maintained as constant as possible withinthe limitations of our experimental apparatus.

2. Experimental method

A schematic of the experimental apparatus isshown in Fig. 1. The fuel bed is mounted in thebottom of a wind tunnel with the sample surfaceflush with the bottom of the tunnel. The wind tun-nel is 550 mm in length with a 130 mm by 80 mmcross section. The sample holder is 150 mm long,100 mm wide and 50 mm deep and its leading edgeis 150 mm from the inlet of the tunnel. Laboratory




J.L. Urban et al. / Proceedings of the Combustion Institute xxx (2014) xxx–xxx 3

air is flown through the wind tunnel with a center-line velocity of 0.5 m/s at the leading edge of thefuel bed.

As is mentioned above, the air flow velocity isa parameter of the problem that affects the rate ofcooling of the particle and the generation of theflammable mixture near the particle; in this studythe air flow velocity was held constant. The airvelocity in this study was chosen because it is onthe order of buoyancy-induced flow speeds (i.e.minimum flow speeds), and it produces a moreregular flow without disturbing the powdered cel-lulose surface. Because of the low flow velocities,the ignition conditions found in this work maynot be representative of those that would beobtained at higher velocities. Flow uniformity isreduced when the tunnel top is opened to intro-duce the particles. To overcome this complexityand ensure a uniform cross-flow velocity betweentests, particles were only dropped on the leadinghalf of the fuel bed. The relative humidity andtemperature of the flow were measured daily andfound to be on average 39:2%� 7:9% and24:0� 2:0 �C respectively. Viewing windows inthe sides of the tunnel allow optical access forSchlieren video recording. The Schlieren systemutilizes a double pass configuration with a colorbullseye (blue1 center, yellow and red rings) anda spherical mirror with a focal length of 1 m.Videos were recorded at 1200 frames per secondusing a digital camera. A high temperature electri-cal furnace is used to heat the metal particles. Alinear guide holds a ceramic spoon approximately140 mm above the fuel bed. This guide is collinearand concentric with the tube furnace such that thespoon can easily be inserted and removed fromthe furnace. A type K thermocouple is embeddedin the spoon to provide a reliable measurement ofthe particle temperature. The metal particles areleft in the oven until their temperature reachesequilibrium conditions as indicated by the ther-mocouple placed in the ceramic spoon. It shouldbe noted that the particle temperature reportedhere is that of the particle in the oven, not atlanding. The particle temperature at landing isobviously lower and dependent on the particlesize, temperature and emissivity. Estimation ofthe temperature reduction during the particledrop is no more than 50 �C for any test.

The fuel bed is powdered cellulose, which waschosen because it is chemically homogeneousand the major component of woody biomass.The cellulose particles have a mean diameter of0.36 mm and at least 80% are 0.42 mm or smalleraccording to manufacturer (Sigma Aldrich) docu-mentation. The average bulk density of the fuelbeds was 338� 40 kg/m3. The cellulose settled

1 For interpretation of color in Fig. 1, the reader isreferred to the web version of this article.


volume was held constant for all experiments.The settled volume refers the minimum volumeoccupied by the fuel bed after vigorous vibration.The fuel beds were laboratory-conditioned andthe moisture content of the fuel was measuredeach day tests were conducted. This involveddrying lab-conditioned samples in an oven at110� 5 �C for at least 4 h. Each sample weighedat least 1.3 g and the mass was measured beforeand after drying. The average moisture contentfor each day was 7:0� 2:0%.

For this study, metal particles composed ofStainless Steel 302, Aluminum 1100, Brass 260,and Copper 110 were heated in the tube furnaceand dropped onto the cellulose fuel bed. Themetal particles studied were either spherical orapproximately spherical in shape. The particlesranged in size from 2 to 11 mm in diameter. Thetemperatures tested ranged from 575 to 1100 �C.The maximum particle temperature was limitedby the maximum operating temperature of thetube furnace. For the range of particles testedno ignition was observed at 575 �C, so furthertests were not conducted below that temperature.Tests using brass and copper were limited totemperatures below their melting points (915 �Cand 1065 �C, respectively) because when thesemetals were heated past their melting point themolten particle would stick to the ceramic spoon.There was no commercially available coatingfound which would prevent this from occurringin an oxidizing environment. As such the maxi-mum temperature used for brass was 900 �C and1050 �C for copper. The relevant thermal proper-ties for the materials are shown in Table 1.

At least five tests were conducted for each par-ticle material at a given diameter and temperature.In order to minimize the effects of random varia-tions in the fuel beds and the penetration of theparticle into the fuel bed, the location where theparticle was dropped was varied and no more thanthree tests were done on a single fuel bed. As wasmentioned in the introduction, the problem hasseveral parameters that can affect the ignitionprocess. However, we feel that the experimentalconditions are well controlled and that five testsis a good data sampling to provide accurateresults, particularly since they are supported bythe physics underlying the ignition problem.

3. Results

The primary objective of this work is to iden-tify the temperature at which particles of a givensize and composition will cause flaming ignitionof the powdered cellulose. During flaming ignitionevents, the flame would initiate around the hotparticle and the heat generation would be suffi-cient to allow the flame to propagate across thefree cellulose surface. The experimental results




Table 1Thermal properties of Stainless Steel 302, Aluminum 1100 (solid and liquid properties), Copper 110 and Brass 260.

Particle material Stainless Steel 302 Al 1100 (solid) Al 1100 (Molten) Cu 110 Brass 260

T s, solidus temperature (�C) 1400 643 643 1065 915T l, liquidus temperature (�C) 1420 657 657 1083 955DHls, heat of melting (kg/m3) 2122 1057 1057 1822 1433q, density (kg/m3) 7860 2710 2375 8890 8530cp, specific heat capacity (J/kg K) 500 900 1141 385 375k, thermal conductivity (W/m K) 21.5 220 90.7 390 120


are shown in Fig. 2. Each of the sub-figures (a–d)corresponds to all of the tests conducted with aparticular metal. The colored circles on the figureeach correspond to a set of at least five tests con-ducted with a particular diameter and tempera-ture particle. The coloring follows a colormapwhich denotes the fraction of those test thatresulted in flaming ignition. Thus a completely

Fig. 2. Observed ignition probabilities fo


black circle corresponds to test conditions whereflaming ignition was never observed and a whitecircle corresponds to a test condition where allof the tests ignited. Intermediate values corre-spond to the colors shown on the color bar inthe center of the figure. Boundaries are providedindicating approximately 5% and 95% probabilityof ignition.

r particles of all four metal types.





Overall the materials follow a similar trend.There is a hyperbolic relationship between particlesize and temperature, with the larger particlesrequiring lower temperatures to ignite the cellu-lose bed. One marked difference between materialswas the range of temperatures over which theobserved chance of ignition was between 5% and95%, for a given size particle. For large sizeparticles, all of the materials except copper hada relatively small range of temperatures wherethe observed ignition probability was between5% and 95% while for copper it was considerablylarger. In the case of aluminum, additional testswere done with a finer temperature resolutionbecause in some cases the range over which igni-tion occurred was so narrow.

4. Discussion

4.1. Ignition phenomenology

Following completion of the experiments, high-speed videos of each of the tests were analyzed. Thevideos of tests where flaming ignition occurred forevery test provide qualitative insight to the pro-cesses that are occurring during ignition. Specifi-cally it can be seen that there is different behaviorbetween tests with very small, high temperatureparticles and tests with large, relatively low temper-ature particles. This is illustrated in 3, which showsthe flaming ignition events of two particles, onewith a diameter of 9:53 mm and heated to 675 �Cshown on the left and a 4:76 mm particle heatedto 900 �C shown on the right.

In the cases with larger particles at lowertemperatures, a dark plume is observed emanatingfrom around the particle at some time after theinitial impact, as is show in the images ofFig. 3a. A dark appearance in a Schlieren imagemeans an object is opaque, suggesting either cellu-lose particles lofted by the particle’s impact orheavier products of pyrolysis are present. The cur-rent resolution of the videos (0.22 mm) means thatthe presence of small lofted cellulose cannot beresolved. However, it should be noted that in thecases of bouncing particles (like the test shownin of Fig. 3a) the plume appears to track the par-ticle, which seems nonphysical for particles loftedby impact. Assuming the cloud is fluid in nature, itseems likely that the opacity is due to condensedpyrolysis products.

For the tests with small particles at higher tem-peratures, we see from the top image of Fig. 3b,that the pyrolyzate plume produced from theimpact site of the particle is transparent, unlikethat of a large diameter particle. This is in contrastto the larger and more violent expansion observedwith larger particles, suggesting larger particlespyrolyze more fuel than required prior to the igni-tion event.


4.2. Parameters controlling ignition

To analyze the results in Fig. 2 it is useful todescribe phenomenologically the thermo-chemicalprocess underlying the ignition of the combustiblefuel bed by a hot metal particle. Once in contactwith the fuel bed the metal particle must transferits energy to the fuel so that it heats up and pyro-lyzes enough material to create a flammable mix-ture of pyrolyzate and air around the metalparticle. In this process the particle temperaturedecreases as its energy decreases (note that energyis also lost to the surrounding environment). Afterthe flammable mixture is formed, it could undergoa pilot type ignition process if the temperature ofthe particle is high enough, or a type of hot spotspontaneous ignition if the conditions are right(gas temperature, heat loses, etc.). Thus, two pri-mary mechanisms appear to control the process,the energy of the particle and its temperature. Alarge particle with low temperature may havelarge energy but not enough temperature to eithercause the thermal decomposition of the materialor the ignition of the pyrolyzate. A small particlemay have a temperature well above the pyrolysistemperature of the fuel or its ignition but notthe energy to pyrolyze enough material to forma flammable mixture.

From the data shown in Fig. 2 it is clear thatthere is different behavior between very largeand very small particles for all of the materialsstudied as with similar studies [15–19]. Figure 4,shows the no-flaming ignition limits for each ofthe four metals. The differences with previousresults from the author’s laboratory [17,18] forsteel and brass particles are due to subsequentimprovements in the determination of the particletemperature. The current experimental approachseems to produce the most accurate results.

From Fig. 4 it can be seen that all the metalsshow similar minimum ignition temperatures fora given diameter, despite large changes in thedifferent metal’s thermal properties, such as theparticle’s density, heat capacity, and thermal con-ductivity. For larger particles the minimum igni-tion temperature is not very sensitive to particlesize. This seems to indicate that particle energyhas a lesser role in the ignition process than thesurface temperature, for larger particles since thephysical properties of the materials are differentand the energy is proportional to the particlevolume. For small particles it is seen that the tem-perature required to achieve ignition is very sensi-tive to size of the particle. This indicates that theparticle energy has a more important role in theignition process than the particle temperature forsmall particles since small reductions in diameterrequires large temperature increases. Furthermoreif we examine the curves corresponding to alumi-num and stainless steel in Fig. 4, we see that 4 mmparticles of aluminum ignite at temperatures




Fig. 4. No ignition limits of the four metals tested withthe ignition limits for comparison.

Fig. 5. Bulk initial energy vs. particle diameter along theno ignition limit.

Fig. 3. Schlieren images prior to and during ignition: note that the larger particle produces a dark, opaque cloud ofpyrolyzate in the first frame while the small particle produces a transparent plume of pyrolyzate. The small bright circlethat appears near the lower middle of all frames is an artifact of the Schlieren imaging technique and is not related to theignition process.


roughly 100 �C lower than their stainless steelcounterparts, but the energies of the two particlesare actually very similar as shown in Fig. 5. Theenergy values shown in Fig. 5 were calculatedassuming constant material properties for eachmaterial phase. The energy released from meltingwas treated as a linear variation over the meltingtemperature range. The energy values were calcu-lated as energy above the ambient temperature.

Furthermore, examining the aluminum igni-tion boundary in Fig. 4 it can be seen that thereis a sharp corner at a diameter of approximately3.5 mm. Between 4 mm and 7 mm diameter theignition limit follows the melting temperaturerange and for diameters greater than 7 mm theignition limit drops below the melting tempera-ture. This indicates that melting has a significanteffect on the potential for the particles to ignitefor diameters greater than 3.5 mm. One possibleexplanation for this is that the molten particleshave considerably greater energy than particlesthat are not molten. When comparing the volu-metric heat of melting to the volumetric heat


capacity (the product of q and cp), it is seen thatthe latent heat of melting adds energy equivalentto the energy gained from heating the aluminumparticle an additional 433 �C. Thus, a completelymolten particle has considerably more energythan a barely molten particle despite the tempera-ture difference of only 15 �C. For particles smallerthan 3.5 mm the aluminum particles behave moreand more like the stainless steel particles indicat-ing that the contribution from the melting energyis not large enough and thus higher temperaturesare needed to provide the required energy to ignitethe fuel.

Copper exhibits some noticeable deviation inignition behavior from the other metals, specifi-cally copper particles require larger temperaturesto ignite than the other metals. It is worth notingthat at temperatures above the liquidus tempera-ture of aluminum, 657 �C, copper has thermalproperties drastically different from the other met-als. Both the thermal conductivity and thermal





diffusivity are at least a factor of three larger thanthe other materials in that range. This wouldallow increased heat transfer from the metalparticle to the cellulose, but would also meanfaster transient temperature changes. As a result,copper patricles may be unable to retain heat longenough for a nascent gas phase reaction tobecome self-sustaining. Based on the higher tem-peratures required for ignition, it seems as thoughthis latter effect is more prominent.

The present ignition results together with thosein [19,17] show that the bulk energy alone is notthe determining factor for ignition to occur. FromFig. 5, it is seen that energy alone does not dictateignition. Specifically, small particles with smallbulk energy can ignite the cellulose, while largeparticles with considerably higher energies cannotignite the cellulose unless they have a sufficientlyhigh temperature. For example, a 10 mm particlewith an initial temperature of 600 �C has approx-imately 6 times the energy of a 4 mm particle at1100 �C and yet the smaller particle will igniteand the larger particle will not. Based on theassumption that some minimum amount of gas-eous fuel is required to initiate a combustion reac-tion, it seems there must be some minimum energyrequirement. However, this appears to be a neces-sary, but not sufficient, condition for ignition.

As was proposed in [19], the exact role of par-ticle temperature and diameter in determiningignition remains unclear. One possibility is thatthe classic balance of heat generation and heatlosses, as proposed by Silver [20] in his study ofgaseous mixture ignition by hot particles, alsoapplies to solid fuels. In his analysis Silver [20],proposed that ignition would occur when the heatgenerated by the incipient combustion reaction ina thin layer around the particle is greater than thelosses to the particle and the surroundings. Igni-tion of a solid fuel is clearly more complicated;because of the higher density of the solid fuel, timeis needed for pyrolysis, and the transport andmixing of the pyrolyzate with the oxidizer [21].During this time, the particle, and the system ingeneral, are losing heat through convection andradiation. In the time required for mass transportto occur, very large particles would lose less heatdue to their large thermal mass, and only a suffi-ciently high initial temperature would be neces-sary for ignition. Very small, high conductivityparticles would lose heat much more rapidly,and thus both a sufficient initial temperature andthermal mass would be required such that the par-ticle and surrounding gases had not cooled off toomuch during the mass transport time. This wouldalso explain the apparent increased sensitivity torandomness for smaller diameters and high con-ductivity metals, as both the mixing time and heatlosses during that time would be affected by thingslike impact dynamics, local fuel bed density, andlocal flow conditions.


5. Conclusion

Tests on the flaming ignition of powdered cel-lulose fuel beds have been performed over a largerange of particle sizes and temperatures for metalsof various thermal properties. These metals arerepresentative of potential sources of ignition ofnatural fuels in practical situations. For large sizeparticles of all of the materials, ignition behaviorappears to be very sensitive to temperature, buttemperature sensitivity appears to decrease withdecreasing size. Data indicates that the energy ofthe particle plays an increasingly important rolefor determining ignition as particle size isdecreased. However, initial particle energy wasshown to be an insufficient indicator of ignitionlikelihood. Ignition was observed in the gas phaseand differences were noted in the behavior ofsmall and large particles. Specifically, large parti-cles tended to produce heavier pyrolyzate prod-ucts and ignite violently, whereas small particlesproduced very little heavier products and ignitedin a more subdued fashion. Overall it was foundthat, except for copper, the thermal properties ofthe material did not have a strong effect on igni-tion except for the effects from melting. The pro-cess of melting adds energy to particles andincreases their ability to ignite, however neitherenergy nor temperature have proven to be the solefactors controlling ignition.

It has been shown that the problem of the igni-tion of a solid fuel bed by a hot metal particle,spark or ember is very complex, involving solidand gas phase thermochemical processes togetherwith geometric and ambient effects. The effects ofparameters such as fuel bed composition andmoisture content, air flow velocity and properties,particles interaction and accumulation, amongothers, will affect the ignition boundaries reportedin this work. However we feel that the presentresults provide a good basic understanding ofthe ignition of fuel beds by hot metal particles.It also provide a data base for verification of the-oretical models of the process.

Acknowledgements

The authors would like to thank Vi Tran,Khanh Do, Adam Martin, Maxime Mense,Andreas Ronellfistch, and Samuel Yoon for theircontributions to this work. This research was sup-ported by National Science Foundation AwardNo. CBET-1066520 and a National Science Foun-dation Graduate Research Fellowship.

References

[1] U.S.F. Administration. <Http://www.usfa.fema.-gov/statistics/estimates/wildfire.shtm> (accessed04.12.14).


http://Http://www.usfa.fema.gov/statistics/estimates/wildfire.shtm

http://Http://www.usfa.fema.gov/statistics/estimates/wildfire.shtm




[2] California Department of Forestry and Fire Pro-tection Investigation Report: Incident number 07-CA-MVU-10432, Technical Report, CaliforniaDepartent of Forestry and Fire Protection, 2008.

[3] A. Maranghides, W. Mell, NIST Technical Note1635: A Case Study of a Community Affected by theWitch and Guejito Fires, Technical Report,National Institute of Standards and Technology,2009.

[4] S. Badger, Large-Loss Fires in the United States –2011, Technical Report, National Fire ProtectionAssociation, U.S., Quincy, Massachusetts 02169,2012.

[5] Emergency Incident Statistics 2009–2010, NewZealand Fire Service, Wellington, New Zealand,2010.

[6] H. Wakelin, Ignition Thresholds for Activity Con-trols on Public Conservation Land in Canterbury,Technical Report, University of Catebury, Cante-bury, NZ, 2010.

[7] C. Egan, S. Holland, The AGE National, 2009.[8] G. Ramsey, N. McArthur, Building in the Urban

Interface: Lessons from the January 1994 SydneyBrushfires, Technical Report, National Institute ofStandards and Technology, Hobart, Tasmania,1995.

[9] J. McGuire, M. Law, J. Miller, Domestic FireHazard Created by Flying Coals and Sprks (FRNote 252), Technical Report, Borehamwood,UK: Fire Research Station, Borehamwood, UK,1956.

[10] NFPA 51B, Standard for Fire Prevention DuringWelding, Cutting and Other Hot Work, 2014 ed.,App. B, National Fire Protection Association, U.S.,Quincy, Massachusetts, 2014.


[11] Fire Risk Managment Journal, 2013. <Https://www.frmjournal.com/mainwebsite/resources/docu-ment/stats%20focus%20march%2010.pdf>.

[12] V. Babrauskas, Ignition Handbook: Principles andApplications to Fire Safety Engineering, Fire Inves-tigation, Risk Management and Forensic Science,Fire Science Publishers, Issaquah, Washington98027, 2003.

[13] M. Ahrens, BRUSH, GRASS, AND FORESTFIRES, Technical Report, National Fire ProtectionAssociation, U.S., Quincy, Massachusetts, 2013.

[14] J.P. Prestemon, T.J. Hawbaker, M. Bowden, J.Carpenter, M.T. Brooks, K.L. Abt, R. Sutphen, S.Scranton, Wildfire Ignitions: A Review of the Scienceand Recommendations for Empirical Modeling,Technical Report, United States Department ofAgriculture: Forest Service, Asheville, NC, 2013.

[15] G. Rowntree, A. Stokes, J. Elec. Electron. Eng.,Aust. 14 (1994) 117–123.

[16] T. Tanaka, Rep. Natl. Res. Inst. Police Sci. 30(1977) 151–158.

[17] R. Hadden, S. Scott, C. Lautenberger, A.C. Fer-nandez-Pello, Fire Technol. 47 (2011) 341–355.http://dx.doi.org/10.1007/s10694-010-0181-x.

[18] C. Zak, D. Murphy, A. Fernandez-Pello, WITTrans. Built Environ. 134 (2013) 607–614, F. Garzia,C.A. Brebbia, M. Guarascio (Eds.), Safety andSecurity Engineering V, WIT Press.

[19] C. Zak, J. Urban, C. Fernandez-Pello, Combust.Sci. Technol., 2014 (accepted for publication).

[20] R. Silver, Philos. Mag. J. Sci. 23 (1937) 633–657.[21] D. Rich, C. Lautenberger, J. Torero, J. Quintiere,

C. Fernandez-Pello, Proc. Combust. Inst. 31 (2007)2653–2660. http://dx.doi.org/10.1016/j.proci.2006.08.055.


http://Https://www.frmjournal.com/mainwebsite/resources/document/stats%20focus%20march%2010.pdf



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Cellulose spot fire ignition by hot metal particles

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