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,P.EWeyerhaeuserRenee.strand@weyerhaeuser.com