1、Designation: C 634 08Standard Terminology Relating toBuilding and Environmental Acoustics1This standard is issued under the fixed designation C 634; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A numbe
2、r in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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. T
3、he 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 mov
4、es 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 I
5、EEE/ 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. Quanti
6、ties 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 instan
7、ce, 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
8、jurisdiction 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
9、.2. Referenced Documents2.1 ASTM Standards:2C 423 Test Method for Sound Absorption and Sound Ab-sorption Coefficients by the Reverberation Room MethodC 367 Test Methods for Strength Properties of PrefabricatedArchitectural Acoustical Tile or Lay-In Ceiling PanelsC 384 Test Method for Impedance and A
10、bsorption ofAcoustical Materials by Impedance Tube MethodC 522 Test Method for Airflow Resistance of AcousticalMaterialsC 635 Specification for the Manufacture, Performance, andTesting of Metal Suspension Systems for Acoustical Tileand Lay-in Panel CeilingsC 636 Practice for Installation of Metal Ce
11、iling SuspensionSystems for Acoustical Tile and Lay-In PanelsC 667 Specification for Prefabricated Reflective InsulationSystems for Equipment and Pipe Operating at Tempera-tures above Ambient AirC 871 Test Methods for Chemical Analysis of ThermalInsulation Materials for Leachable Chloride, Fluoride,
12、Silicate, and Sodium IonsE90 Test Method for Laboratory Measurement of AirborneSound Transmission Loss of Building Partitions and Ele-mentsE 336 Test Method for Measurement of Airborne SoundAttenuation between Rooms in BuildingsE 413 Classification for Rating Sound InsulationE 477 Test Method for Me
13、asuring Acoustical and AirflowPerformance of Duct Liner Materials and PrefabricatedSilencersE 492 Test Method for Laboratory Measurement of ImpactSound Transmission Through Floor-Ceiling Assemblies1This terminology is under the jurisdiction of ASTM Committee E33 onBuilding and Environmental Acoustic
14、s and is the direct responsibility of Subcom-mittee E33.07 on Definitions and Editorial.Current edition approved March 15, 2008. Published April 2008. Originallyapproved in 1969. Last previous edition approved in 2002 as C 634 02e1.2For referenced ASTM standards, visit the ASTM website, www.astm.org
15、, 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 the Tapp
16、ing MachineE 497 Practice for Installing Sound-Isolating LightweightPartitions3E 557 Guide for The Installation of Operable PartitionsE 596 Test Method for Laboratory Measurement of NoiseReduction of Sound-Isolating EnclosuresE 756 Test Method for MeasuringVibration-Damping Prop-erties of MaterialsE
17、 795 Practices for Mounting Test Specimens DuringSound Absorption TestsE 966 Guide for Field Measurements of Airborne SoundInsulation of Building Facades and Facade ElementsE 989 Classification for Determination of Impact InsulationClass (IIC)E 996 Practice for Reporting Data in Auger Electron Spec-
18、troscopy and X-ray Photoelectron SpectroscopyE 1007 Test Method for Field Measurement of TappingMachine Impact Sound Transmission Through Floor-Ceiling Assemblies and Associated Support StructuresE 1014 Guide for Measurement of Outdoor A-WeightedSound LevelsE 1042 Classification for Acoustically Abs
19、orptive MaterialsApplied by Trowel or SprayE 1050 Test Method for Impedance and Absorption ofAcoustical Materials UsingATube, Two Microphones andA Digital Frequency Analysis SystemE 1110 Classification for Determination of ArticulationClassE 1111 Test Method for Measuring the Interzone Attenua-tion
20、of Open Office ComponentsE 1123 Practices for Mounting Test Specimens for SoundTransmission Loss Testing of Naval and Marine ShipBulkhead Treatment MaterialsE 1124 Test Method for Field Measurement of SoundPower Level by the Two-Surface MethodE 1130 Test Method for Objective Measurement of SpeechPri
21、vacy in Open Offices Using Articulation IndexE 1179 Specification for Sound Sources Used for TestingOpen Office Components and SystemsE 1222 Test Method for Laboratory Measurement of theInsertion Loss of Pipe Lagging SystemsE 1265 Test Method for Measuring Insertion Loss of Pneu-matic Exhaust Silenc
22、ersE 1289 Specification for Reference Specimen for SoundTransmission LossE 1332 Classification for Determination of Outdoor-IndoorTransmission ClassE 1374 Guide for Open Office Acoustics and ApplicableASTM StandardsE 1375 Test Method for Measuring the Interzone Attenua-tion of Furniture Panels Used
23、as Acoustical Barriers3E 1376 Test Method for Measuring the Interzone Attenua-tion of Sound Reflected by Wall Finishes and FurniturePanels3E 1408 Test Method for Laboratory Measurement of theSound Transmission Loss of Door Panels and Door Sys-temsE 1414 Test Method for Airborne Sound Attenuation Be-
24、tween Rooms Sharing a Common Ceiling PlenumE 1433 Guide for Selection of Standards on EnvironmentalAcousticsE 1503 Test Method for Conducting Outdoor Sound Mea-surements Using a Digital Statistical Sound AnalysisSystemE 1573 Test Method for Evaluating Masking Sound in OpenOffices Using A-Weighted an
25、d One-Third Octave BandSound Pressure LevelsE 1574 Test Method for Measurement of Sound in Residen-tial SpacesE 1686 Guide for Selection of Environmental Noise Mea-surements and CriteriaE 1704 Guide for Specifying Acoustical Performance ofSound-Isolating EnclosuresE 1779 Guide for Preparing a Measur
26、ement Plan for Con-ducting Outdoor Sound MeasurementsE 1780 Guide for Measuring Outdoor Sound Received froma Nearby Fixed SourceE 2179 Test Method for Laboratory Measurement of theEffectiveness of Floor Coverings in Reducing ImpactSound Transmission Through Concrete FloorsE 2202 Practice for Measure
27、ment of Equipment-GeneratedContinuous Noise for Assessment of Health HazardsE 2235 Test Method for Determination of Decay Rates forUse in Sound Insulation Test MethodsE 2249 Test Method for Laboratory Measurement of Air-borne Transmission Loss of Building Partitions and Ele-ments Using Sound Intensi
28、tyIEEE/ 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 MeasurementsANSI S1.11 Octave-Band and Fractional O
29、ctave-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, for a given frequency, thecomplex quotient obtai
30、ned 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 as solid walls,3Withdrawn.4Available from Amer
31、ican National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.C634082buildings, 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,
32、are sufficiently wide and high to cause significantreduction of the sound traveling from the source to thereceiver.acoustical materialany material considered in terms of itsacoustical properties. Commonly and especially, a materialdesigned to absorb sound.admittance ratio, yrc grcjbrc; dimensionless
33、thereciprocal of the impedance ratio. The real and imaginarycomponents are called, respectively, conductance ratio andsusceptance ratio.airborne soundsound that arrives at the point of interest,such as one side of a partition, by propagation through air.airflow resistance, R; ML4T1; mks acoustic ohm
34、 (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 volumevelocity may be either steady or alternating.airflow resistivity, ro; ML3T1; mks rayl/m (Pas/m2)of ahomogeneous material, the quo
35、tient of its specific airflowresistance divided by its thickness.ambient noisethe composite of airborne sound from manysources near and far associated with a given environment.No particular sound is singled out for interest.arithmetic mean sound pressure levelof several relatedsound pressure levels
36、measured at different positions ordifferent times, or both, in a specified frequency band, thesum of the sound pressure levels divided by the number oflevels.DISCUSSIONThe arithmetic mean sound pressure level is sometimesused to approximate the average sound pressure level. The accuracyof this appro
37、ximation depends upon the range of sound pressure levels.average sound pressure levelof several related soundpressure levels measured at different positions or differenttimes, or both, in a specified frequency band, ten times thecommon logarithm of the arithmetic mean of the squaredpressure ratios f
38、rom which the individual levels were de-rived.DISCUSSION1An average sound pressure level obtained by aver-aging the A-weighted sound level continuously over a specified periodis called the time-average sound level.DISCUSSION2Since, by definition, a squared pressure ratio, pi2/p02, is equal to 10Li/1
39、0, 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 pressure levels,pi= rms pressure at an individual position or time, or both,Pa,p0= 20 Pa, reference sound pressure, andLi= an individ
40、ual 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 specified timeinterval, dB,T =t2t1= a specified time interval, s, min, h, or day,p(t) = instantaneous sound pressure, Pa, andp0= 20 Pa
41、, reference sound pressure.background noisenoise from all sources unrelated to aparticular sound that is the object of interest. Backgroundnoise may include airborne, structureborne, and instrumentnoise.characteristic impedance of the medium, rc; ML2T1;mks rayl (Pas/m)the specific normal acoustic im
42、pedanceat a point in a plane wave in a free field. It is a pure specificresistance since the sound pressure and the particle velocityare in phase and it is equal in magnitude to the product of thedensity of the medium, r, and the speed of sound in themedium, c. Its value when the medium is air at 20
43、C and101.325 kPa is 413 mks rayl (Pas/m).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
44、 system.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 te
45、n times 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 li
46、kequantities, 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 disconti
47、nuity,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 ha
48、selectrical 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 E 413using values of field transmission loss.field transmissi
49、on loss, FTLsound transmission loss mea-sured in accordance with Annex A1 of Test Method E 336.flanking transmissiontransmission of sound from theC634083source to a receiving location by a path other than that underconsideration.impact insulation class, IICa single-number rating derivedfrom measured values of normalized impact sound pressurelevels in accordance with Annex A1 of Test Method E 492.It provides an estimate of the impact sound insulatingperformance of a floor-ceiling assembly.impedance
