ROOFROOF OPERATIONSOPERATIONS COURSECOURSE OUTLINEOUTLINE IntroductionIntroduction PARTPART II--PhasesPhases ofof StructureStructure FiresFires PARTPART IIII--RoofRoof ConstructionConstruction PARTPART IIIIII--TacticalTactical ConsiderationsConsiderations PARTPART IVIV--VentilationVentilation MethodsMethods INTRODUCTIONINTRODUCTION AA considerableconsiderable portionportion ofof thethe annualannual lossloss ofof lifelife andand propertyproperty isis aa directdirect resultresult ofof thethe lacklack ofof timely,timely, effectiveeffective ventilationventilation 80%80% ofof allall firefire fatalitiesfatalities areare duedue toto smokesmoke inhalationinhalation MoreMore thanthan oneone--halfhalf ofof thethe nationsnations firefire lossloss isis aa directdirect resultresult ofof smokesmoke andand heatheat damagedamage VentilationVentilation hashas aa directdirect effecteffect onon allall aspectsaspects ofof firefire fightingfighting strategiesstrategies PARTPART II PHASESPHASES OFOF STRUCTURESTRUCTURE FIRESFIRES PHASESPHASES OFOF STRUCTURESTRUCTURE FIRESFIRES StructureStructure firesfires progressprogress throughthrough threethree basicbasic phases:phases: –– IncipientIncipient oror BeginningBeginning PhasePhase –– SteadySteady StateState oror FreeFree--BurningBurning PhasePhase –– HotHot SmolderingSmoldering PhasePhase PhasesPhases ofof FireFire THETHE INCIPIENTINCIPIENT // BEGINNINGBEGINNING PHASEPHASE OxygenOxygen contentcontent approximatelyapproximately 21%.21%. CarbonCarbon dioxide,dioxide, sulfursulfur dioxide,dioxide, carboncarbon monoxidemonoxide andand waterwater vaporvapor produced.produced. TheThe flameflame temperaturetemperature cancan bebe aboveabove 10001000 degrees,degrees, whilewhile roomroom temperaturetemperature maymay onlyonly bebe slightlyslightly elevated.elevated. PhasesPhases ofof firefire STEADYSTEADY STATESTATE // FREEFREE--BURNINGBURNING PHASEPHASE AdequateAdequate oxygenoxygen andand fuelfuel sustainsustain freefree-- burningburning andand firefire growthgrowth toto thethe pointpoint ofof fullfull involvementinvolvement ofof area/room.area/room. –– MushroomingMushrooming –– FlashoverFlashover PhasesPhases ofof FireFire STEADYSTEADY STATESTATE // FREEFREE--BURNINGBURNING PHASEPHASE MushroomingMushrooming –– SmokeSmoke andand gasesgases areare heated.heated. –– IfIf confinedconfined toto aa roomroom oror building,building, theythey willwill riserise toto thethe uppermostuppermost level.level. –– CoolerCooler airair isis displaceddisplaced downdown towardstowards thethe fire,fire, providingproviding oxygenoxygen andand sustainingsustaining combustion.combustion. –– AsAs circulationcirculation occurs,occurs, heatedheated smokesmoke andand gasesgases buildbuild internalinternal pressurepressure thatthat continuecontinue toto riserise andand spreadspread laterally.laterally. PhasesPhases ofof FireFire STEADYSTEADY STATESTATE // FREEFREE--BURNINGBURNING PHASEPHASE FlashoverFlashover –– AA simultaneoussimultaneous ignitionignition overover thethe surfacesurface ofof thethe roomroom oror area.area. –– OccursOccurs whenwhen thethe heatheat fromfrom thethe firefire raisesraises thethe temperaturetemperature ofof thethe contentscontents toto theirtheir ignitionignition temperatures.temperatures. –– TheThe ignitionignition happenshappens inin anan instant.instant. –– EffectsEffects maymay bebe deadlydeadly toto firefightersfirefighters PhasesPhases ofof FireFire HOTHOT SMOLDERINGSMOLDERING PHASEPHASE IfIf thethe freefree--burningburning statestate remainsremains unun--vented,vented, thethe firefire progressesprogresses intointo thethe hothot smolderingsmoldering phase.phase. –– LowLow oxygenoxygen levelslevels withwith littlelittle oror nono flameflame production.production. –– TemperaturesTemperatures inin excessexcess ofof 10001000 degrees.degrees. –– DenseDense blackblack smoke,smoke, thatthat pressurizespressurizes thethe area.area. –– IntenseIntense heatheat continuescontinues toto vaporizevaporize lighterlighter fuels.fuels. –– TheseThese gasesgases greatlygreatly increaseincrease thethe chancechance ofof aa backdraft.backdraft. PhasesPhases ofof FireFire HOTHOT SMOLDERINGSMOLDERING PHASEPHASE BackdraftBackdraft –– AA confinedconfined areaarea thatthat isis teemingteeming withwith pressurized,pressurized, heatedheated andand flammableflammable gases.gases. –– TheThe introductionintroduction ofof oxygenoxygen toto thisthis fuelfuel--richrich environmentenvironment willwill resultresult inin anan explosionexplosion ofof significantsignificant intensity.intensity. –– EffectsEffects maymay bebe deadlydeadly toto firefightersfirefighters PartPart IIII ROOFROOF CONSTRUCTIONCONSTRUCTION RoofRoof ConstructionConstruction TheThe firefightersfirefighters abilityability toto safelysafely andand efficientlyefficiently ventilateventilate aa buildingbuilding throughthrough thethe roofroof willwill dependdepend toto somesome degreedegree onon hishis understandingunderstanding ofof roofroof constructionconstruction ItIt isis essentialessential thatthat firefightersfirefighters becomebecome familiarfamiliar withwith thethe existingexisting andand newlynewly constructedconstructed buildingsbuildings withinwithin theirtheir responseresponse areaarea RoofRoof ConstructionConstruction ConventionalConventional VSVS LightweightLightweight CONVENTIONALCONVENTIONAL CONSTRUCTIONCONSTRUCTION RoofRoof ConstructionConstruction ConventionalConventional ConstructionConstruction StructuralStructural membersmembers dependdepend onon sizesize forfor strength.strength. LessLess surfacesurface areaarea exposedexposed toto fire.fire. TheThe largerlarger thethe sizesize ofof aa structuralstructural member,member, thethe longerlonger itit willwill taketake toto failfail whenwhen exposedexposed toto fire.fire. PotentiallyPotentially longerlonger burnburn timetime resultsresults inin aa greatergreater windowwindow ofof safetysafety forfor firefire fighters.fighters. RoofRoof ConstructionConstruction ArchedArched TrussesTrusses BuildingsBuildings builtbuilt duringduring thethe 19301930’’ss andand 19401940’’ss commonlycommonly usedused trusstruss construction.construction. TrussTruss membersmembers havehave thethe samesame strengthstrength relationshipsrelationships asas lightweightlightweight onlyonly muchmuch stronger.stronger. RoofRoof ConstructionConstruction BridgeBridge TrussesTrusses BuildingsBuildings builtbuilt inin thethe 19201920’’ss--19401940’’ss notnot asas commoncommon asas thethe archarch RoofsRoofs varyvary inin sizesize andand slightlyslightly inin designdesign TopTop surfacesurface isis basicallybasically aa flatflat roofroof RoofRoof ConstructionConstruction ConventionalConventional ResidentialResidential RoofRoof ConstructionConstruction ConventionalConventional ResidentialResidential RoofRoof ConstructionConstruction RAFTERSRAFTERS ANDAND SPACESPACE SHEETINGSHEETING RoofRoof ConstructionConstruction ConventionalConventional ConstructionConstruction FirefighterFirefighter ConcernsConcerns –– GenerallyGenerally soundsound constructionconstruction –– StrongestStrongest areasareas ofof thesethese roofsroofs areare ridges,ridges, hips,hips, valleys,valleys, overover trussestrusses andand wherewhere raftersrafters crosscross outsideoutside wallswalls –– SizeSize ofof structuralstructural membermember dictatesdictates firefire exposureexposure timetime priorprior toto failurefailure –– HeatHeat holesholes areare acceptableacceptable andand preferredpreferred withwith thisthis typetype ofof constructionconstruction RoofRoof ConstructionConstruction LIGHTWEIGHTLIGHTWEIGHT CONSTRUCTIONCONSTRUCTION RoofRoof ConstructionConstruction LightweightLightweight construction:construction: DoesDoes notnot derivederive itsits strengthstrength fromfrom size.size. StrengthStrength obtainedobtained fromfrom multiplemultiple membersmembers inin compressioncompression andand tension.tension. InvolvesInvolves thethe useuse ofof lessless firefire resistiveresistive materials.materials. ProvidesProvides lessless timetime toto ventilateventilate beforebefore thethe roofroof becomesbecomes unstable.unstable. RoofRoof ConstructionConstruction LightweightLightweight ConstructionConstruction GeneralGeneral RulesRules –– ExpectExpect earlyearly andand completecomplete collapsecollapse –– NoNo heatheat holesholes –– CutCut ventvent holesholes wellwell aheadahead ofof firefire –– 3/83/8--1/21/2”” deckingdecking offersoffers littlelittle resistanceresistance toto firefire –– TimeTime onon thesethese roofsroofs isis veryvery limitedlimited RoofRoof ConstructionConstruction MajorMajor typestypes ofof LightweightLightweight roofroof constructionconstruction MetalMetal GussetGusset PlatePlate Trusses.Trusses. WoodenWooden ““II”” Beam.Beam. OpenOpen WebWeb Truss.Truss. OpenOpen WebWeb SteelSteel JoistJoist PanelizedPanelized RoofRoof ConstructionConstruction MetalMetal GussetGusset PlatePlate Trusses:Trusses: CommonCommon inin residentialresidential andand commercialcommercial buildings.buildings. UsuallyUsually 22”” xx 44”” lumberlumber buttbutt jointedjointed andand heldheld togethertogether byby metalmetal gussetgusset platesplates commonlycommonly knownknown asas ““ganggang nailnail”” whichwhich areare 3/83/8”” inin depth.depth. CharacterizedCharacterized byby aa toptop (compression)(compression) chordchord andand bottombottom (tension)(tension) chord.chord. SpansSpans upup toto 8080’’ withwith trussestrusses 22’’ onon centercenter RoofRoof ConstructionConstruction LightweightLightweight CommercialCommercial