【英文标准名称】:StandardPracticeforCalculatingDesignValueTreatmentAdjustmentFactorsforFire-Retardant-TreatedLumber
【原文标准名称】:耐火处理木材设计参数调节系数的计算标准实施规程
【标准号】:ASTMD6841-2008
【标准状态】:现行
【国别】:美国
【发布日期】:2008
【实施或试行日期】:
【发布单位】:美国材料与试验协会(US-ASTM)
【起草单位】:D07.07
【标准类型】:(Practice)
【标准水平】:()
【中文主题词】:
【英文主题词】:designvalues;fire-retardant;fire-retardanttreatment;lumber;mechanicalproperties;strengthproperty;thermaleffects;Ambienttemperature;Clearwoodevaluation/testing;Compressionparalleltograin;Compressiontesting--wood/woodproducts;Design
【摘要】:Fire-retardant-treatmentsareusedtoreducetheflame-spreadcharacteristicsofwood.Chemicalsandredryingconditionsemployedintreatmentsareknowntomodifythestrengthpropertiesofthewoodproductbeingtreated.Thispracticegivesproceduresforfire-retardantchemicalmanufacturerstousetocalculatetheeffectsoftheirtreatmentonlumberusedinnormalandelevatedtemperatureserviceconditions.Theeffectoffire-retardanttreatmentsonthestrengthoflumberusedinroofframingapplicationsistimerelated.Inthispractice,thecumulativeeffectonstrengthofannualthermalloadsfromalltemperaturebinsisincreased50timestoestablishtreatmentadjustmentfactorsforfire-retardanttreatedlumberroofframing.TheproceduresofTestMethodD5664employanelevatedtemperatureintendedtoproducestrengthlossesinashortperiodoftime.Althoughtheexposureismuchmoreseverethanthatwhichoccursinanactualroofsystem,thechemicalreactionsthatoccurinthelaboratorytestareconsideredtobethesameasthoseoccurringoverlongperiodsoftimeinthefield.Treatmentadjustmentfactorsdevelopedunderthispracticeapplytolumberinstalledinaccordancewithconstructionpracticesrecommendedbythefire-retardantchemicalmanufacturerwhichincludeavoidanceofdirectwetting,precipitationorfrequentcondensation.Applicationofthispracticeislimitedtoroofapplicationswithdesignconsistentwith1.3.1.1Thispracticecoversproceduresforcalculatingtreatmentadjustmentfactorstobeappliedtodesignvaluesforfire-retardant-treatedlumberusedatambienttemperatures[servicetemperaturesupto100x00B0;F(38x00B0;C)]andasframinginroofsystems.1.2Thesedesignvaluetreatmentadjustmentfactorsforthepropertiesofextremefiberinbending,tensionparalleltograin,compressionparalleltograin,horizontalshear,andmodulusofelasticityarebasedontheresultsofstrengthtestsofmatchedtreatedanduntreatedsmallclearwoodspecimensafterconditioningatnominalroomtemperatures[72x00B0;F(22x00B0;C)]andofothersimilarspecimensafterexposureat150x00B0;F(66x00B0;C).ThetestdataaredevelopedinaccordancewithTestMethodD5664.Guidelinesareprovidedforestablishingadjustmentfactorsforthepropertyofcompressionperpendiculartograinandforconnectiondesignvalues.1.3TreatmentadjustmentfactorsforroofframingapplicationsarebasedoncomputergeneratedthermalloadprofilesfornormalwoodroofconstructionusedinavarietyofclimatesasdefinedbyweathertapesoftheAmericanSocietyofHeating,RefrigeratingandAir-ConditioningEngineers,Inc.(ASHRAE).Thesolarloads,moistureconditions,ventilationrates,andotherparametersusedinthecomputermodelwereselectedtorepresenttypicalslopedroofdesigns.Thethermalloadsinthispracticeareapplicabletoroofslopesof3in12orsteeper,toroofsdesignedwithventareasandventlocationsconformingtonationalstandardsofpracticeandtodesignsinwhichthebottomsideoftheroofsheathingisexposedtoventilationair.Fordesignsthatdonothaveoneormoreofthesebase-linefeatures,theapplicabilityofthispracticeneedstobedocumentedbytheuser.1.4TheproceduresofthispracticeparallelthosegiveninPracticeD6305.GeneralreferencesandcommentaryinPracticeD6305arealsoapplicabletothispractice.1.5Thevaluesstatedininch-poundunitsaretoberegardedasstandard.TheSIunitslistedinparenthesesareprov......
【中国标准分类号】:B70
【国际标准分类号】:79_040
【页数】:6P.;A4
【正文语种】:英语