wood-framed, exterior walls in type iii construction ww 4 ... · are choosing type iii construction...
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Wood-Framed,ExteriorWallsinTypeIIIConstructionwithEngineeredWoodProductFloorFraming
Disclaimer:ThispresentationwasdevelopedbyathirdpartyandisnotfundedbyWoodWorksortheSoftwoodLumberBoard.
Withthetrendtowardincreaseddensity,moredesignersarechoosingTypeIIIConstructioninordertoachievegreaterheightsandareasfortheirmid-risewood-framedprojects.Thispresentationwillreview2015IBCprovisionsforwood-framedexteriorwallsinTypeIIIbuildings ascomparedtoTypeV.Discussionwill includehowtomaintaintheintentofthecodeatthewall-to-floorintersectionsinscenariosthatincludewood-framedwallsandengineeredwoodfloors.Detailsillustratingtheimportanceofcorrectrimspecificationwhenusingplatformframingandforsemi-ballooned framedwallswillalsobeprovided.
CourseDescription
Objectives1. 2015IBCcodeprovisiondifferencesbetweenTypeVandTypeIII
construction.
2. Definitionoffire-retardant-treated(FRT)wood,whatmaterialscanbetreated,andreductionstodesignpropertiesduetotreatment.
3. Requiredfire-resistanceratingsandmaintainingthoseratingsatthewalltofloorintersection.
4. Structuralsignificanceofproperrimspecificationwithplatformframinganddetailingforsemi-balloonedframedwalls.
ArchitecturalDetails StructuralDetails
R4R3
UseandOccupancyClassifications
R1
R2ResidentialGroupR• IBCSection310
TypeofConstruction
Type V
Type IV
Type I & II
Type III
TYPEV TYPEIV TYPEIII TYPEII TYPEI
SizeofB
uilding →
TypeofConstruction
FireResistanceRequirements
FireResistance…
TypeOfConstruction2015IBCChapter5,GeneralBuildingHeightsandAreas• Section504- Height
TypeOfConstruction2015IBCChapter5,GeneralBuildingHeightsandAreas• Section504- Stories
CheckLocalCodeAmendments
CityofSeattleallows5storiesforTypeV
TypeOfConstruction2015IBCChapter5,GeneralBuildingHeightsandAreas• Section504- Area
SomeexceptionsSection505.2– Mezzanines
• Partofstorybelow• Shallnotexceed1/3thefloorareaitisoccupying
Section506.3– FrontageIncrease• Moreareapermittedwhenaccesstopublicway• 25%ofbuildingperimeteronpublicway• Publicwayoropenspaceatleast20ft wide
Section510.5– GroupR-1andR-2buildingsofTypeIIIAconstruction• Increaseto6stories
MaterialsAllowedforTypesofConstructionTypeV– Section602.5
• Anymaterialpermittedbycode
• MostcommonforEWP
TypeIII– Section602.3
• Non-combustibleexteriorwallsor
• Fire-retardanttreated(FRT)woodallowed
• Interiorbuilding elementsanymaterial
permittedbycodeCheckLocalCodeAmendments
FRTWoodDefinedinIBCsection2303.2
• Wood impregnatedwithchemicalsbyapressureprocessorothermeansduringmanufacturing
• Testing:• FlameSpreadindexof25orless(10min) PLUS• ExtendedATSME84(30min)• Noevidenceofsignificantprogressivecombustion• Flamefrontshallnotprogressmorethan10.5ft
ClassAFlameSpread≠ FRT• StrengthAdjustmentsFactors
• WoodStructuralPanels• Lumber
• Labeled
FRTWood• EvaluationReportsforFRTChemicals
• Lumber• Plywood
• Species• StrengthReductions• Corrosion• FastenerReductions
FRTWood PlatformFramingChallenge:MostSCL/GLB:• notevaluated
afterFRT• Dimensional
changes• SCL/GLBnot
warrantedafterpressuretreatment
• CheckwithSCL/GLBmanufacturer
Fire-ResistanceRatingsforBuilding
Fire-ResistanceRatedAssembliesIBCSection703.3Methodsfordeterminingfireresistance.Establishedby
1. Designsperapprovedsources2. PrescriptiveperSection7213. CalculatedperSection7224. EngineeringanalysisbasedonASTME119orUL2635. AlternatemeansperSection104.116. CertifiedDesigns
Fire-ResistanceRatedAssembliesResources:• InternationalBuildingCode• Intertek• UnderwritersLaboratories• GypsumAssociation• Manufacturer’sliterature/code
evaluationreports• AmericanWoodCouncil(DCA3)• APA(D350A)
Fire-ResistanceRatedAssemblies
Whataretherequirementswhenthefloorframingintersectstheexteriorwall?
Semi-BalloonedFramedWallsThingstoconsider
• Hangers• TallerStuds• Schedulingtrades• Designconsiderations
• Connections• Eccentricity
• Notpreferred
PlatformFramedWallsThingstoconsider• Preferred
• EliminateHangers• ConsistentStudHeights
PlatformFramedWalls
Section705– ExteriorWalls• 705.6Structuralstability.
• Bandjoisttobeoffire-resistantconstruction• Equivalentfireresistancetothewall• Floorjoistsdonotrequirefire-resistanceequalto
thewall• SeeTable601
RatingtoRim=ceilingrating+directappliedprotection
PlatformFramedWallsTypeIIIA
• Wall- 2-hr• Floor- 1-hr• Additional1-hrprotectionrequiredfor
rimtototal2-hrrating
TypeIIIB• Wall– 2hr• Floor– 0-hr• Directapplied2-hrprotectionrequired
PlatformFramedWalls
APAwalldetails–D350A
CeilingMembrane+DirectAppliedProtectionRimBoardProtection
PlatformFramedWalls
Interek Listing
4.RimBoardProtection:Direct-appliedprotectionlistedintable,itemsA-E.
FRTWoodNeedcompatiblerimforengineeredwoodfloorframing
Q. RimFRT?
RimSpecificationCriticalStructuralComponent• Transferverticalloads• Transferlateralloads• CompatiblewithI-Joists
• SamedepthasI-joistorslightlygreater• Maintaindepthcompatibility
• IBCSection2303.1.13• ConformtoANSI/APAPRR410orASTMD7672• Depthcompatibility
FramingDetailsOptions?• Widerimwithjoisthangers• CheckwithEWPmanufacturer’sforproprietarysolutions
• AC124“AcceptanceCriteriaforRimBoardProducts• Section7.0“Factory-AppliedFire-RetardantOverlaid
orCoatedRimBoardforInteriorApplications”
Review• DifferencesbetweenTypeVandTypeIIIconstruction
• FRTWorequivalentatexteriorwalls• 2-hrfire-resistanceratedwalls
• FRTwood• DimensionLumberorPlywoodhavebeenevaluated
• ClassAFlameSpread≠ FRT• Fire-resistanceratings
• TypeIIIexteriorrim2-hrfire-resistancerating• Totalrating=ceilingprotection+rimprotection• 2layerceilingforEWPjoists
• Details• Platformframing– properrimspecification• Semi-balloonedframedwalls- hangers
Questions?This concludes the American Institute of Architects
Continuing Education System Program
ReneeStrand,[email protected]