1、Designation: C 634 08aStandard 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 numb
2、er 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. 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 Sept. 1, 2008. Published October 2008. Originallyapproved in 1969. Last previous edition approved in 2008 as C 634 08.2For 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 Tappi
16、ng 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 1007 Test Method for Field Measurement of TappingMachine
18、 Impact Sound Transmission Through Floor-Ceiling Assemblies and Associated Support StructuresE 1014 Guide for Measurement of Outdoor A-WeightedSound LevelsE 1042 Classification for Acoustically Absorptive MaterialsApplied by Trowel or SprayE 1050 Test Method for Impedance and Absorption ofAcoustical
19、 Materials UsingATube, Two Microphones andA Digital Frequency Analysis SystemE 1110 Classification for Determination of ArticulationClassE 1111 Test Method for Measuring the Interzone Attenua-tion of Open Office ComponentsE 1123 Practices for Mounting Test Specimens for SoundTransmission Loss Testin
20、g 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 SpeechPrivacy in Open Plan Spaces Using Articulation IndexE 1179 Specification for Sound Sources Used for Testin
21、gOpen 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 SilencersE 1289 Specification for Reference Specimen for SoundTransmission LossE 1332 Classification for
22、Determination of Outdoor-IndoorTransmission ClassE 1374 Guide for Open Office Acoustics and ApplicableASTM StandardsE 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-tween Rooms Sharing a C
23、ommon 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 and One-Third Octave Band
24、Sound 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 Measurement Plan for Con-duct
25、ing 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 Measurement of Equipment-Gener
26、atedContinuous 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 IntensityE 2459 Guide for Meas
27、urement of In-Duct Sound PressureLevels 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, a
28、ndBand Numbers for Acoustical MeasurementsANSI 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 a
29、cousticohm (Pas/m3)of a surface, for 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.acousti
30、cal barriercontiguous objects such 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
31、the sound traveling from the source to thereceiver.3Withdrawn.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.C 634 08a2acoustical materialany material considered in terms of itsacoustical properties. Commonly and especia
32、lly, 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 arrives at the point of interest,such as one side of a
33、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 volumevelocity may be either steady or alternating.
34、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 environment.No particular sound is singled out for i
35、nterest.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.DISCUSSIONThe arithmetic mean sound pressure level is some
36、timesused 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 differenttimes, or both, in a specified frequency band,
37、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 specified periodis called the time-average sound level.DI
38、SCUSSION2Since, 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 pressure levels,pi= rms pressure at an individual
39、 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 specified timeinterval, dB,T =t2t1= a specified ti
40、me 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, structureborne, and instrumentnoise.cutoff freque
41、ncyof 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 system.decay rate, d; T1; dB/sfor airborne sound, the
42、 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 times the commonlogarithm of the ratio of two like q
43、uantities 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 likequantities, it has no dimensions. It is, however, co
44、mmon 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,such as the edge of a reflective or absorptive s
45、urface.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 haselectrical characteristics identical to a functional
46、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 transmission loss, FTLsound transmission loss mea-sured in accor
47、dance with Annex A1 of Test Method E 336.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 normalized impact sound pressurelevels in accordan
48、ce with Annex A1 of Test Method E 492.It provides an estimate of the impact sound insulatingperformance of a floor-ceiling assembly.impedance ratio, z/rc r/rc + jx/rc; dimensionlesstheratio of the specific normal acoustic impedance at a surfaceto the characteristic impedance of the medium. The real
49、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, usuallyC 634 08a3characterized 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 exists to unequivocallydefine the presence of imp
