Page 431 - konishipaper

a
σ1000
Q) 弘司 ロ ro L吋 Q) 0.
5500
Mature
Declin巴
. Q) 0.
1500
inthewholehouse;(3)thefiredeclinestageinwhichthe majorpartofthehousecolapsedandthefiredeclined.
Thefolowingphenomenawereobservedassignsofthe firesupresionefectsbyaerialfirefightinginthethre stages.
Inthefireexpansionstage，blacksmokeroseimedi- atelyaftertheignition.Burningwasintenseandflames wereblowingofnearthewindowsastherewasmuch oxygen.AlthoughthetemperaturesofCh-2(10cm)and Ch-3 (170cm) reached close to the highest temperature withinabout10minafterignition，ittokabout25minfor thetemperatureofCh-l (50cm)toreachtothehighest temperature.Thisshowsthatittokmuchtirneuntilthe firespreadintotheinsideofthehouse.Althoughthehouse temperaturefeltemporarilybywaterspraying，itwentup againwithin1mininthefireexpansionstage.
Inthefirematurestage，thetemperatureofthehousedid not fluctuate much and was burning at temperature of about10oC.Thewalsofthehousewereburneddown and the fire expanded to the whole house 30min after ignition.Althoughthedeclineofthehousetemperatureby watersprayinginthefirematurestagewassmalerthan
thatinthefireexpansionstage，ittoklongertorecoverto thetemperaturebeforewaterspraying.
Inthefiredeclinestage，smokewashardlygenerated， andtherepeatedwatersprayingnolongercausedthehouse temperaturetorecovertothetemperaturebeforewater spraying.However，60rninaftertheignition，thetempera- tureofCh-2begantoriseagain.Thiswasbecausethescrap woodthatremainednearthethermocoupleCh-2wasstil burning.Theimageanalysisbytheinfraredcamerasshows thatthetemperatureofthewholehousewasfalingandthe firewasonthedeclinestage.
Fig.7(b)showsthepenetrationofdroppedwaterinto thecenterhouseA3.Thecumu1atedamountofwateris shownonthehorizontalaxis，andhousetemperatureis shownontheverticalaxis.Symbolplus(+)showsthat droppedwaterhitthehouse.TheCh-l，Ch-2andCh-3are thermocouples，whichmeasurethetemperatureatheightof 50，10，and170cm，respectively，fromtheground.
The penetration of dropped water into the house is influencedbycoveragelevelofdropwater，theexistenceof arof，andhowthescrapwoodwaspiledupinthehouse. Fromthefirsttothe4thchalengesofaerialfirefighting，
T.Konishieta.l/FireSafetyJournα143(208)363-375 369
O
O 20 40 60 80 10 120
O
Time(min.)
b 1500
HouseA3
，.-. 10 U
O
U
包
吋
e 500
ト
Fig.7.(a)Thetemp巴raturechangesofthecenterhouseA3afterignitionuntilthefireextinguishedinthefirstexp巴riment.(b)Thetemperaturechanges， whichindicatethepenetrationofdropp巴dwaterintothecenterhous巴 A3.
O 5 10 15 Cumulativewateramount(ton)
9
・
マ upwind
/':，. downwind
T right-sidewind A left-sidewind + hittohous巴
一 Chl(50cm) 一一一 Ch2(lOcm) ー一叩 Ch3(170cm)