Page 432 - konishipaper

370 T.Konishieta.l/FireSafeり)Journα143(208)363-375
theternperatureofCh-1(50crn)decreasedgreat1y，which indicatesthatwaterpenetratedintothehouse.Inthe8th， the12thtothe14thandthe16thtothe20thchalenges，the ternperature of Ch-1 decreased on1y slight1y，which indicatesthatwaterdidnotfulypenetrateintothehouse. Inthefireexpansionstage，theternperatureofCh-1rose steadilyinspiteofwaterdroping.Inthe白rernaturestage， the supresion efects by water droping were not observed.Duringthe8th，l3th，16th，17th，18thand20th chal lenges with high coverage 1eve1 to the house， the ternperaturedropwassrnal，a1thoughdropingwaterhit thehouse.Astothereasonsforthisserning1yinadequate functioningofthethernocoup1eCh-1，thefolowingthre causescanbediscused:(1)sincethernocoup1esarepoint instrurnentation，dropingwaterdidnothitCh-1;(2)since theburningternperaturenearthethernocoup1ewashigh， dropingwaterevaporatedbeforeitreachedtoCh-1;(3) thesheathofthethernocoup1eCh-1wasdarnagedbyfire and exact ternperature was not rneasured.However， considering-thefactsthattheternperaturefelgradualy as water drop ping continued，and in the 12th and 17th
chalenges，theternperaturefelgreat1y，itcanbeconcluded thatthecauseswere(1)and(2).
Fig.8(a) shows the ternperature of house B4 after ignitionunti1thefirewasextinguished.Syrnbo1p1us(+) showsthatdroppedwaterhitthecenterhouseB4.Thefour triang1esyrnbo1sshowwinddirectionstowardhouseB4 frornareaswherewaterwasdropped.Syrnbo1triang1e(ム)， solidtriang1e(企)， invertedtriang1e(マ)andsolidinverted triang1e(T)representupwind，downwind，right-sidewind and 1eft-sidewind，respective1y. The Ch-6 and Ch-7 are thernocouples，whichrneasuretheternperatureinsidethe house at a height of 50 and 10 0crn frorn the ground， respectively.
Thedurationofthefirewasdividedintothefolowing threstagesbyanalyzingtheinfraredandvideoirnages:(1) thefireexpansionstage;(2)thefirernaturestage;and(3) thefirerekind1estage，inwhichthefireflaredupagain.The 5thdropingofwaterwasdoneon1yagainsthouseB4and the rekindle started 30rnin after the 5th drop ping. The ternperature ofCh-6 (50crn) reached to 800C within about10rninafterignition，whenthefirespreadintothe
a
Expansion
l‘ ，l‘
150，
JIJI
b 150寸 σ1000
O
U . 2 お ら司
~0. 5500
1'" ' 1 " "
HouseB5
1 " " 1 Tim巴 (min.)
2345
O
1 " " l' '" 1 " "
20 40 60 80 10
1
V
/:，.
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企
一
一 一 一
Mature
Rekindle
upwind downwind right-sidewind left-sidewind
Ch6(50cm) Ch7(lOOcm)
+++
O
O 5 10 15 20 25 30 35
Cumulativewateramount(ton)
Fig.8. (a)ThetemperaturechangesofthecenterhouseB4afterignitionuntilthefireextinguishedinthesecondexperiment.(b)Th巴 temperaturechanges， whichindicatethepen巴trationofdropp巴dwat巴rintothecenterhous巴 B4.
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