Designation:C423−17StandardTestMethodforSoundAbsorptionandSoundAbsorptionCoefficientsbytheReverberationRoomMethod1ThisstandardisissuedunderthefixeddesignationC423;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheU.S.DepartmentofDefense.1.Scope1.1Thistestmethodcoversthemeasurementofsoundabsorptioninareverberationroombymeasuringdecayrate.Proceduresformeasuringtheabsorptionofaroom,theabsorptionofanobject,suchasanofficescreen,andthesoundabsorptioncoefficientsofaspecimenofsoundabsorptivematerial,suchasacousticalceilingtile,aredescribed.1.2FieldMeasurements—Althoughthistestmethodcoverslaboratorymeasurements,thetestmethoddescribedin4.1canbeusedformakingfieldmeasurementsoftheabsorptionofrooms(seealso5.5).AmethodtomeasuretheabsorptionofroomsinthefieldisdescribedinTestMethodE2235.1.3Thistestmethodincludesinformationonlaboratoryaccreditation(seeAnnexA1),asymmetricalscreens(seeAn-nexA2),andreverberationroomqualification(seeAnnexA3).1.4ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitsofmeasurementareincludedinthisstandard.1.5Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:2C634TerminologyRelatingtoBuildingandEnvironmentalAcousticsE795PracticesforMountingTestSpecimensDuringSoundAbsorptionTestsE2235TestMethodforDeterminationofDecayRatesforUseinSoundInsulationTestMethods2.2ANSIStandards:S1.6PreferredFrequencies,FrequencyLevels,andBandNumbersforAcousticalMeasurements3S1.11SpecificationforOctave-BandandFractional-Octave-BandAnalogandDigitalFilters3S1.26MethodfortheCalculationoftheAbsorption...
