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工 Konishietal.fSafetyScience53(2013)73-81 79
Fig.12.Photographsofmock-upboatforareproducibilitytestthatwascariedoutwithamock-upboatunderconditionssimilartotheactualacident:(a)a70kgwater tank，equivalenttotheweightoftheboatoperator，wasplacedontheIidofthestarboardcompartment，(b)fueltankthathada1mmholeinthebotom，(c)anidentical bateryandIifeveststhatplacedinthestarboardcompartment，and(d)anignitingsparkwasartificialygeneratedbycontactingthepositiveandnegativeelectrodesofthe batery.
holemayresultinthestrongexplosioninthecompartmentC(the secondvesel).
4.4.Boatexplosionreprodudbilitytest
Final1y.inordertoconfirmthepresumedmechanismofthe acident.areproducibilitytestwascariedoutwithamock-up boatunderconditionssimilartotheactualacident(Fig. 12a). Sincetheoriginalfueltankwasevidence.anidenticalonewaspre- paredforthereproducibilitytest.asshowninFig.12b.A 1m m holewasboredinthebottomofthetank.sothatasmalquantity ofIiquidgasolinewouldleakout.AnidenticalbateryandIifevests wereplacedinthestarboardcompartmentshowninFig.12c.A
70kgwatertank.equivalenttotheweightoftheboatoperator. wasplacedonthelidofthestarboardcompartment.Anigniting sparkwasartificialygeneratedbycontactingthepositiveandneg- ativeelectrodesofthebateryshowninFig.12d.Thebuildupof gasolinevaporinthestarboardcompartmentwasfolowedwith theHCgasdetector.untiltheconcentrationexcededthelean flammablelimit.Asthevaporconcentrationinthecompartments ofthemock-upboatwaspredictedbytheresultsofthedifusion experiments.therequiredignitiontimewasreadilyestimated.
Fig.13showsaseriesofphotographsofthereproducibilitytest. Sincetheignitiontimeofgasolinevaporwasunknown.theelapsed timesindicatedinthefigurecaptionsarenotacurate.TheIidof theportsidecompartmentandtheworkdeckwereblownupby
Fig.13.Photographsshowaseriesofphotographsofthereproducibilitytest.Photographsat:(a)0ms，(b)10ms，(c)30ms，and(d)50msafterignition.