1、Designation: C634 10aStandard Terminology Relating toBuilding and Environmental Acoustics1This standard is issued under the fixed designation C634; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number
2、 in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.INTRODUCTIONIn some of the entries, those that are measures of physical quantities, the term is followed by threeitems: symbol, dimensions, and unit. The
3、 symbol, in italics, stands for the magnitude of the quantityin mathematical expressions. The dimensions of a quantity express its measure in terms of threefundamental quantities: M for mass, L for length, and T for time. Speed, for instance, is the quotientobtained when the distance an object moves
4、 is divided by the time involved. The dimensions areLT1, the negative exponent indicating division. The unit is consistently in SI, Le SystmeInternational dUnits. Those still using the cgs (centimetre-gram-second) or the inchpound system ofunits are referred for most of the conversion factors to IEE
5、E/ ASTM SI 10. A few conversion factorsare listed in Section 4 of this terminology.The dimensions of a quantity are the same regardless of the units in which the quantity is measured.Speed has the dimensions LT1 whether it is measured in miles per hour, feet per second, or metresper second. Quantiti
6、es with different dimensions are not the same. Flow resistance and specific flowresistance, for instance, are quantities of different kinds even though the names are similar. On theother hand, quantities with the same dimensions are not necessarily of the same kind. Sound energydensity, for instance
7、, has the same dimensions as sound pressure, ML1T2, but it is not a kind ofsound pressure. Nor is absorption with the dimensions L2 a kind of area.1. Scope1.1 This terminology covers terms and definitions related toenvironmental acoustics. Only definitions common to two ormore standards under the ju
8、risdiction of Committee E33 arelisted here. The purpose of this terminology is to promoteuniformity of key definitions. Definitions pertinent to only onestandard and exceptions to the definitions listed below arecontained in the individual standards and should be used whenfollowing those standards.2
9、. Referenced Documents2.1 ASTM Standards:2C423 Test Method for Sound Absorption and Sound Ab-sorption Coefficients by the Reverberation Room MethodC367 Test Methods for Strength Properties of PrefabricatedArchitectural Acoustical Tile or Lay-In Ceiling PanelsC384 Test Method for Impedance andAbsorpt
10、ion ofAcous-tical Materials by Impedance Tube MethodC522 Test Method for Airflow Resistance of AcousticalMaterialsC635 Specification for the Manufacture, Performance, andTesting of Metal Suspension Systems for Acoustical Tileand Lay-in Panel CeilingsC636 Practice for Installation of Metal Ceiling Su
11、spensionSystems for Acoustical Tile and Lay-In PanelsC667 Specification for Prefabricated Reflective InsulationSystems for Equipment and Pipe Operating at Tempera-tures above Ambient AirC871 Test Methods for Chemical Analysis of ThermalInsulation Materials for Leachable Chloride, Fluoride,Silicate,
12、and Sodium IonsE90 Test Method for Laboratory Measurement of AirborneSound Transmission Loss of Building Partitions and Ele-mentsE336 Test Method for Measurement of Airborne SoundAttenuation between Rooms in BuildingsE413 Classification for Rating Sound InsulationE477 Test Method for Measuring Acous
13、tical and AirflowPerformance of Duct Liner Materials and PrefabricatedSilencersE492 Test Method for Laboratory Measurement of ImpactSound Transmission Through Floor-Ceiling Assemblies1This terminology is under the jurisdiction of ASTM Committee E33 onBuilding and Environmental Acoustics and is the d
14、irect responsibility of Subcom-mittee E33.07 on Definitions and Editorial.Current edition approved Sept. 1, 2010. Published December 2010. Originallyapproved in 1969. Last previous edition approved in 2010 as C634 10. DOI:10.1520/C0634-10A.2For referenced ASTM standards, visit the ASTM website, www.
15、astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Using
16、the Tapping MachineE497 Practice for Installing Sound-Isolating LightweightPartitions3E557 Guide for The Installation of Operable PartitionsE596 Test Method for Laboratory Measurement of NoiseReduction of Sound-Isolating EnclosuresE756 Test Method for Measuring Vibration-Damping Prop-erties of Mater
17、ialsE795 Practices for Mounting Test Specimens During SoundAbsorption TestsE966 Guide for Field Measurements of Airborne SoundInsulation of Building Facades and Facade ElementsE989 Classification for Determination of Impact InsulationClass (IIC)E1007 Test Method for Field Measurement of TappingMachi
18、ne Impact Sound Transmission Through Floor-Ceiling Assemblies and Associated Support StructuresE1014 Guide for Measurement of Outdoor A-WeightedSound LevelsE1042 Classification for Acoustically Absorptive MaterialsApplied by Trowel or SprayE1050 Test Method for Impedance and Absorption ofAcoustical
19、Materials UsingATube, Two Microphones andA Digital Frequency Analysis SystemE1110 Classification for Determination of ArticulationClassE1111 Test Method for Measuring the InterzoneAttenuationof Open Office ComponentsE1123 Practices for Mounting Test Specimens for SoundTransmission Loss Testing of Na
20、val and Marine ShipBulkhead Treatment MaterialsE1124 Test Method for Field Measurement of Sound PowerLevel by the Two-Surface MethodE1130 Test Method for Objective Measurement of SpeechPrivacy in Open Plan Spaces Using Articulation IndexE1179 Specification for Sound Sources Used for TestingOpen Offi
21、ce Components and SystemsE1222 Test Method for Laboratory Measurement of theInsertion Loss of Pipe Lagging SystemsE1265 Test Method for Measuring Insertion Loss of Pneu-matic Exhaust SilencersE1289 Specification for Reference Specimen for SoundTransmission LossE1332 Classification for Rating Outdoor
22、-Indoor Sound At-tenuationE1374 Guide for Open Office Acoustics and ApplicableASTM StandardsE1408 Test Method for Laboratory Measurement of theSound Transmission Loss of Door Panels and Door Sys-tems3E1414 Test Method for Airborne Sound Attenuation Be-tween Rooms Sharing a Common Ceiling PlenumE1433
23、 Guide for Selection of Standards on EnvironmentalAcoustics3E1503 Test Method for Conducting Outdoor Sound Mea-surements Using a Digital Statistical Sound AnalysisSystemE1573 Test Method for Evaluating Masking Sound in OpenOffices Using A-Weighted and One-Third Octave BandSound Pressure LevelsE1574
24、Test Method for Measurement of Sound in Residen-tial SpacesE1686 Guide for Applying Environmental Noise Measure-ment Methods and CriteriaE1704 Guide for Specifying Acoustical Performance ofSound-Isolating EnclosuresE1779 Guide for Preparing a Measurement Plan for Con-ducting Outdoor Sound Measuremen
25、tsE1780 Guide for Measuring Outdoor Sound Received froma Nearby Fixed SourceE2179 Test Method for Laboratory Measurement of theEffectiveness of Floor Coverings in Reducing ImpactSound Transmission Through Concrete FloorsE2202 Practice for Measurement of Equipment-GeneratedContinuous Noise for Assess
26、ment of Health HazardsE2235 Test Method for Determination of Decay Rates forUse in Sound Insulation Test MethodsE2249 Test Method for Laboratory Measurement of Air-borne Transmission Loss of Building Partitions and Ele-ments Using Sound IntensityE2459 Guide for Measurement of In-Duct Sound PressureL
27、evels from Large Industrial Gas Turbines and FansIEEE/ ASTM SI 10 Standard for Use of the InternationalSystem of Units (SI): The Modern Metric System2.2 ANSI Standard:ANSI S1.4 Specification for Sound Level Meters4ANSI S1.6 Preferred Frequencies, Frequency Levels, andBand Numbers for Acoustical Meas
28、urementsANSI S1.11 Octave-Band and Fractional Octave-BandAna-log and Digital Filters, Specifications for3. Terminology3.1 If the term sought by the user cannot be found in 3.2,itmay be found in 4.1.3.2 Terms and Definitions:acoustic impedance, Z R + jX; ML4T1; mks acousticohm (Pas/m3)of a surface, f
29、or a given frequency, thecomplex quotient obtained when the sound pressure aver-aged over the surface is divided by the volume velocitythrough the surface. The real and imaginary components arecalled, respectively, acoustic resistance and acoustic reac-tance.acoustical barriercontiguous objects such
30、 as solid walls,buildings, or earthen berms that substantially block the directpath of sound between a source and receiver, and which, ifthey have an open edge or edges allowing diffraction aroundthem, are sufficiently wide and high to cause significantreduction of the sound traveling from the sourc
31、e to thereceiver.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.C634 10a2acoustical materialany material considered in terms
32、of itsacoustical properties. Commonly and especially, a materialdesigned to absorb sound.admittance ratio, yrc grcjbrc; dimensionlessthereciprocal of the impedance ratio. The real and imaginarycomponents are called, respectively, conductance ratio andsusceptance ratio.airborne soundsound that arrive
33、s at the point of interest,such as one side of a partition, by propagation through air.airflow resistance, R; ML4T1; mks acoustic ohm (Pas/m3)the quotient of the air pressure difference across aspecimen divided by the volume velocity of airflow throughthe specimen. The pressure difference and the vo
34、lumevelocity may be either steady or alternating.airflow resistivity, ro; ML3T1; mks rayl/m (Pas/m2)of ahomogeneous material, the quotient of its specific airflowresistance divided by its thickness.ambient noisethe composite of airborne sound from manysources near and far associated with a given env
35、ironment.No particular sound is singled out for interest.arithmetic mean sound pressure levelof several relatedsound pressure levels measured at different positions ordifferent times, or both, in a specified frequency band, thesum of the sound pressure levels divided by the number oflevels.DISCUSSIO
36、NThe arithmetic mean sound pressure level is sometimesused to approximate the average sound pressure level. The accuracyof this approximation depends upon the range of sound pressure levels.average sound pressure levelof several related soundpressure levels measured at different positions or differe
37、nttimes, or both, in a specified frequency band, ten times thecommon logarithm of the arithmetic mean of the squaredpressure ratios from which the individual levels were de-rived.DISCUSSION1An average sound pressure level obtained by aver-aging the A-weighted sound level continuously over a specifie
38、d periodis called the time-average sound level.DISCUSSION2Since, by definition, a squared pressure ratio, pi2/p02, is equal to 10Li/10, average sound pressure level is calculated fromthe expression:Li5 10 logS1n(i 5 1n10Li/10Dwhere:Lp= average sound pressure level, dB,n = number of individual sound
39、pressure levels,pi= rms pressure at an individual position or time, or both,Pa,p0= 20 Pa, reference sound pressure, andLi= an individual sound pressure level, dB.If conditions warrant, an integral expression may be used:Lp5 10 logS1T*t1t2p2t!/p02! dtDwhere:Lp= average sound pressure level during a s
40、pecified timeinterval, dB,T =t2t1= a specified time interval, s, min, h, or day,p(t) = instantaneous sound pressure, Pa, andp0= 20 Pa, reference sound pressure.background noisenoise from all sources unrelated to aparticular sound that is the object of interest. Backgroundnoise may include airborne,
41、structureborne, and instrumentnoise.cutoff frequencyof an anechoic wedge or set of wedges, thelowest frequency above which the normal incidence soundabsorption coefficient is at least 0.990.dampto cause a loss or dissipation of the oscillatory orvibrational energy of an electrical or mechanical syst
42、em.decay rate, d; T1; dB/sfor airborne sound, the rate ofdecrease of sound pressure level after the source of soundhas stopped; for vibration, the rate of decrease of vibratoryacceleration, velocity, or displacement level after the exci-tation has stopped.decibel, dBthe term used to identify ten tim
43、es the commonlogarithm of the ratio of two like quantities proportional topower or energy. (See level, sound transmission loss.)Thus, one decibel corresponds to a power ratio of 100.1andn decibels corresponds to a power ratio of (100.1)n.DISCUSSIONSince the decibel expresses the ratio of two likequa
44、ntities, it has no dimensions. It is, however, common practice totreat “decibel” as a unit as, for example, in the sentence, “The averagesound pressure level in the room is 45 decibels.”diffractiona change in the direction of propagation of soundenergy in the neighborhood of a boundary discontinuity
45、,such as the edge of a reflective or absorptive surface.diffuse sound fieldthe sound in a region where the intensityis the same in all directions and at every point.direct sound fieldthe sound that arrives directly from asource without reflection.dummy microphonea microphone substitute which haselec
46、trical characteristics identical to a functional micro-phone, but which has essentially no sensitivity to incidentsound pressure.field sound transmission class, FSTCsound transmissionclass calculated in accordance with Classification E413using values of field transmission loss.field transmission los
47、s, FTLsound transmission loss mea-sured in accordance with Annex A1 of Test Method E336.flanking transmissiontransmission of sound from thesource to a receiving location by a path other than that underconsideration.impact insulation class, IICa single-number rating derivedfrom measured values of nor
48、malized impact sound pressurelevels in accordance withAnnexA1 of Test Method E492.Itprovides an estimate of the impact sound insulating perfor-mance of a floor-ceiling assembly.impedance ratio, z/rc r/rc + jx/rc; dimensionlesstheratio of the specific normal acoustic impedance at a surfaceto the char
49、acteristic impedance of the medium. The real andimaginary components are called, respectively, resistanceratio and reactance ratio.impulsive sound, na brief, intrusive sound, such as thatassociated with a tire blowout, operation of a punch press,the discharge of a firearm, a door slam, or a shout, usuallyC634 10a3characterized by a rapid rise time in the initial pressure pulseof less than a few milliseconds, and by a decay time of lessthan a few seconds.DISCUSSIONNo mathematical description exist
