作者:标准资料网 时间:2024-05-25 03:02:42   浏览:9552   来源:标准资料网

【英文标准名称】:StandardTestMethodforFieldMeasurementofSoundPowerLevelbytheTwo-SurfaceMethod
【原文标准名称】:双表面法现场测量声功率级的标准试验方法
【标准号】:ASTME1124-2010
【标准状态】:现行
【国别】:美国
【发布日期】:2010
【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】:E33.08
【标准类型】:(TestMethod)
【标准水平】:()
【中文主题词】:
【英文主题词】:fieldsoundpower;industrialnoise;machinerynoise;soundpower;two-surfacemethod;Acousticaltests;Ambientsoundpressurelevels;Bandfiltersets;Concavemeasurementsurfaces;Conformalmeasurementsurfaces;Convexmeasurementsurfaces;Fieldtes
【摘要】:Thefunctionandoperationofequipmentinthefieldoftenprecludethemeasurementofthefree-fieldsoundpressurelevelsofasinglepieceofequipmentintheabsenceofinterferingsoundfromotherequipmentoperatingatthesametime.Thetwo-surfacemethodwillprovide,inmostcases,areliableestimateofthenormalsoundpowerlevelsofaspecimenoperatinginanadverseenvironment.Thistestmethodisintendedforuseinthefieldinthepresenceofwhatisnormallyregardedasinterferingbackgroundnoise.ThistestmethodisbasedupontheworkofHubner,andDiehl,butdiffersfromallothercurrentsoundpowermeasurementproceduresbyrequiringsimultaneousmeasurementatbothconformalsurfacesandbyresolvingtime-averagedsoundpressurelevelsatbothsurfacestowithin0.1dB.Thesetwofeatures,simultaneousrecordingand0.1dBresolution,enablesourcesoundpowertobecalculatedwhenthedirectsoundfieldofthesourceisactuallylowerinlevelthantheambientnoise.Theuseofthistestmethodisexpectedtobeprimarilyfortherelativeassessmentofthesoundpowerfromsimilarsourcesorforthepredictionofsoundlevelsinaplantbaseduponmeasurementsofsimilarsourcesinanotherplant.Thistestmethodisbelievedtobecapableofyieldingareasonablygoodestimateofabsolutepowerlevelwithpropercareofapplicationandfullconformancetotheprovisionsofthisprocedure.Thetwo-surfacemethodisapplicableonlywhenthetwomeasurementsurfacescanbephysicallyselectedtoproducepositivevaluesofthedifferenceinaveragesoundpressurelevel.Thatis,theinnersurfacesoundpressurelevelminustheoutersurfacesoundpressurelevelmustbeatleast+0.1dB.Thislimitationappliestoeachfrequencybandandeachconstituentsurfaceareainvestigated.Onlythefrequencybandinwhichazeroornegativedifferenceoccursisitconsideredinvalidandusuallyadjacentbandswillbevalid.Inpractice,onlyrarelywillallthreeone-thirdoctavebandsofagivenoctaveyieldinvaliddataatallconstituentareas.Therefore,lessthancompleteresultsarepermissiblewhenone-thirdoctaveanalysisisusedandfulloctaveresultsarereported.Thetwo-surfacemethodmaynotproduceresultswhentestingsomeverylargemachinesinveryreverberantroomsorinroomshavingavolumelessthanabout20timesthespaceenclosedbyanenvelopearoundthelargerdimensionsofthemachine.Insuchcases,thesoundpressurelevelclosetothemachinemaynotdecreaseinanyregularwaywithincreasingdistancefromamachinesurface,makingitimpossibletoselecttwomeasurementsurfacesproducingpositivedifferencesofsoundpressurelevel.1.1Thistestmethodcoversthefield,orinsitumeasurementofsoundpowerlevelbythetwo-surfacemethod.Thetestmethodisdesignedtominimizetheeffectsofreverberantconditions,directivityofthenoisesourceunderconsideration,andtheeffectsofambientnoisefromothernearbyequipmentoperatingatthesametime.1.2Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappropriatesafetyandhealthpracticesanddeterminetheapplicabilityofregulatorylimitationspriortouse.
【中国标准分类号】:A42
【国际标准分类号】:17_140_0
【页数】:7P.;A4
【正文语种】:英语