1、Designation: E 1130 02e1Standard Test Method forObjective Measurement of Speech Privacy in Open OfficesUsing Articulation Index1This standard is issued under the fixed designation E 1130; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revis
2、ion, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.e1NOTEFootnote 4 was added editorially in March 2002.INTRODUCTIONThis is one of a series of test methods for eva
3、luating the acoustical characteristics of open officeenvironments and the performance of acoustical components. Other proposed test methods in thisseries deal with the laboratory measurement of interzone attenuation of partial height space dividersand ceiling systems.1. Scope1.1 This test method des
4、cribes a means of measuring speechprivacy objectively between locations in open offices. This testmethod relies upon acoustical measurements, published infor-mation on speech levels, and standard methods for assessingspeech communication. This test method does not measure theperformance of individua
5、l open office components which affectspeech privacy; it measures the privacy which results from aparticular configuration of components (1, 2).21.2 This test method is intended to be a field test for themeasurement of speech privacy in actual open offices. How-ever, this test method could be used in
6、 an environmentarranged to simulate an open office.1.3 This test method could be adapted for use in other openplan spaces such as open plan schools. It could also be adaptedfor measuring the speech privacy between open plan andenclosed spaces or between fully enclosed spaces.1.4 This test method rel
7、ies upon the Articulation Indexwhich predicts the intelligibility of speech for a group oftalkers and listeners. While both the Articulation Index and thistest method can be expected to reliably predict average speechprivacy, neither predicts the specific degree of speech privacyafforded to particul
8、ar open office occupants.1.5 The values stated in SI units are to be regarded as thestandard. The inch-pound units in parentheses are for informa-tion only.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of
9、 this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:C 384 Test Method for Impedance and Absorption ofAcoustical Materials by the Impedance Tube Method3C 634 Terminology
10、Relating to Environmental Acoustics3E 1041 Guide for Measurement of Masking Sound in OpenOffices4E 1179 Specification for Sound Sources Used for TestingOpen Office Components and Systems32.2 ANSI Standards:5S1.4 Specification for Sound Level MetersS1.6 Preferred Frequencies and Band Numbers for Acou
11、s-tical MeasurementsS1.11 Specification for Octave, Half-Octave and One-ThirdOctave Band Filter Sets3. Terminology3.1 DefinitionsThe acoustical terminology used in thistest method is consistent with Terminology C 634. Of specialimportance are the terms average sound pressure level andarithmetic mean
12、 sound pressure level, both of which aredefined in Terminology C 634, and source point which isdefined in Specification E 1179.1This test method is under the jurisdiction of ASTM Committee E33 onEnvironmental Acoustics and is the direct responsibility of Subcommittee E33.02 onOpen Plan Spaces.Curren
13、t edition approved Jan. 10, 2002. Published February 2002. Originallypublished as E 1130 86. Last previous edition E 1130 90 (1994)e1.2The boldface numbers in parentheses refer to the list of references at the end ofthis test method.3Annual Book of ASTM Standards, Vol 04.06.4Discontinued. See 2001 A
14、nnual Book of ASTM Standards, Vol 04.06.5Available from American National Standards Institute, 11 W. 42nd St., 13thFloor, New York, NY 10036.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4. Summary of Test Method4.1 Select two loca
15、tions in an open office environment,between which the speech privacy is to be measured. Designateone location as the talker or source location and the other as thelistener or measurement location. These locations should typifythe usual working positions of office occupants.4.2 All masking sound syst
16、ems and HVAC systems shall beoperating in their usual manner.4.3 At the listener location, measure the ambient soundpressure levels in each one-third octave-band from 200 to 5000Hz and the A-weighted sound level.4.4 Locate a qualified sound source at the talker locationand orient it toward the liste
17、ner location. Drive the source withpink or white noise at a level sufficient to increase the one-thirdoctave-band sound pressure levels at the measurement locationby at least 10 dB above the ambient over the entire frequencyrange of interest. The sound pressure levels produced by thesound source at
18、a 0.9-m (3-ft) reference position for a knownelectrical input will have been previously established (3).4.5 Measure the sound pressure levels in one-third octavebands at the listener location with the source on.4.6 Calculate the level reduction in each one-third octaveband, that is, the difference i
19、n sound pressure levels producedby the sound source at 0.9 m (3 ft) and at the listener location.4.7 Determine the speech spectra to be used. The normalvoice spectrum of male speech peaks from Table 1 must beused; optionally, additional spectra may be used.4.8 Calculate the one-third octave-band sou
20、nd pressurelevels for the speech spectrum at the listener location. This iscarried out by subtracting the measured level reductions fromthe speech spectrum.4.9 Calculate the signal-to-noise ratio in each one-thirdoctave band by subtracting the measured ambient and soundpressure levels from the calcu
21、lated speech levels at the listenerlocation.4.10 Calculate the Articulation Index in accordance withSection 11 using the one-third octave-band signal-to-noiseratios.4.11 Report the Articulation Index to two decimal places asthe measure of speech privacy.5. Significance and Use5.1 The speech privacy
22、between open offices is determinedby the degree to which intruding speech sounds from adjacentoffices exceed the ambient sound pressure levels at the listen-ers ear; a classic signal-to-noise ratio situation.5.2 The sound pressure levels at the listeners ear fromspeech in adjacent offices depend upo
23、n:5.2.1 The individual vocal effort and orientation of thetalker,5.2.2 The attenuation of speech signals due to distance orintervening barriers, and5.2.3 The reinforcement of speech signals due to reflectionsfrom office surfaces such as the ceiling, furniture panels, lightfixtures, walls, or windows
24、.5.3 The ambient sound pressure levels will usually becontrolled to mask intruding speech. This is accomplished bymeans of a masking sound system. However, in certainpositions and frequency ranges, heating, ventilating, or airconditioning equipment (HVAC) may contribute significantlyto ambient sound
25、 pressure levels. Guide E 1041 may be used tomeasure masking sound.5.4 The primary purpose of this test method is to measurethe speech privacy for an average speech spectrum using thestandard Articulation Index method. This requires measure-ment of the relevant acoustical characteristics discussed i
26、n 5.2and 5.3 for a pair of offices and calculation of the ArticulationIndex using an average speech spectrum. The average speechspectrum is for male talkers speaking with normal voice effort.5.5 The Articulation Index ranges from 0.00, where speechis unintelligible, to 1.00, where all individual spo
27、ken words canbe understood. Caution should be exercised in interpreting thenumerical results of this test method. There is a need for furtherresearch to establish the relationship of Articulation Index tospeech privacy. One purpose of this test method is to encouragethe measurement of data and furth
28、er research on this topicperhaps leading to development of well-documented speechprivacy categories and criteria.5.6 This test method can be used to:5.6.1 Compare the relative privacy afforded between differ-ent pairs of open offices.5.6.2 Evaluate how changes in open office components(barriers, fur
29、niture, ceilings, masking sound, or wall panels)affect speech privacy.5.6.3 Measure speech privacy objectively for correlationwith subjective responses.5.7 This test method could be one element of a performanceor acceptance test procedure. However, many additional itemswould need to be specified to
30、use this test method forperformance testing of an open office environment, such as, theTABLE 1 Speech Peaks for MalesA,BOne-ThirdOctave-BandCenterFrequency,HzOne-ThirdOctave-BandSound PressureLevels ofSpeech Peaksfor NormalVoice Effort(dB re: 20 Pa)One-ThirdOctave-BandSound PressureLevels ofSpeech P
31、eaksfor RaisedVoice Effort(dB re: 20 Pa)200 60 63250 64 68315 63 67400 65 70500 66 72630 64 70800 58 661000 58 651250 59 671600 56 632000 52 592500 53 603150 53 584000 50 565000 46 52ASpeech peaks calculated from rms values given in Ref (4) by adding 12 db, inaccordance with (7). Values given in Ref
32、 (4) are normalized to 1 m and are usedin this test method as representative values for 0.9 m.BThe A-weighted sound level and linear sound pressure level of the normal voiceeffect spectrum given in Table 1 are 70 dBA and 73 dB, respectively. Thecorresponding levels for the raised voice effort spectr
33、um are 76 dBA and 78 dB.These may be compared to the levels for the “idealized speech peak spectrum”given in Table 8 of ANSI S3.5, 74 dBA and 77 dB.(7)E 11302number of office pairs to be tested and method of selectingthose offices, and the method of averaging the results. Speci-fying a numerical cri
34、terion in terms of the Articulation Index isalso necessary for acceptance testing; however, the selection ofsuch a criterion and permissible deviations should be under-taken with care in view of the present state-of-the-art asdiscussed in 5.5.5.8 Recent data on speech levels as discussed in Ref (4)
35、arenormalized to 1 m (3.3 ft). However, recently developed testmethods for evaluating open office components and systems,including this test method, have been developed using dis-tances standardized in U.S. customary units (feet). This testmethod assumes that speech levels at 0.9 m (3 ft) and1mareeq
36、uivalent. This is a reasonable and conservative assumptionconsidering that the standard deviation of normal voice speechlevels is several decibels or more as discussed in Ref (4). Usinga point source model of spherical spreading, the difference insound pressure levels between 0.9 and1m(3and3.3ft)wou
37、ldbe at most 1 dB.6. Test Space6.1 The test space shall be an actual or a mock-up openoffice environment.6.2 The ceiling of the test space shall be complete, includingceiling board, light fixtures, and air diffusers.6.3 The floor covering and wall finishes shall be completelyinstalled prior to testi
38、ng.6.4 Office furnishings shall be in place.6.5 Any masking sound system shall be set as intended foruse in the occupied space.NOTE 1If the masking system is adjusted to produce significantlyhigher sound pressure levels, greater speech privacy is obtained; however,the higher levels may be found unac
39、ceptably annoying.6.6 The open office space should be unoccupied during thetests.NOTE 2If the purpose of testing is to evaluate the change in speechprivacy which results from component changes (for example, installingwall finishes or adjusting the masking system) the different conditions foreach tes
40、t result shall be carefully documented.7. Apparatus7.1 The minimum instrumentation required for this testmethod is as follows:7.1.1 Microphone and Amplifier, that meet or exceed therequirements of ANSI S1.4 for Type 1 sound level meters. Arandom incidence microphone shall be used, that is, one thath
41、as its flattest frequency response for sounds arriving atrandom angles.7.1.2 One-Third Octave-Band Filter Set, meeting the re-quirements of ANSI S1.11 for Order 3 or higher, Type 1 orbetter. The nominal center frequencies of the filters shallinclude all the preferred one-third octave bands from 200
42、to5000 Hz conforming to ANSI S1.6. This range may beextended.7.1.3 Sound Level Meter, Graphic Level Recorder, or otherdevice from which the sound pressure level can be read.7.1.4 Calibrated Sound Source, of known sensitivity anddirectivity, completely described in Specification E 1179 andcalibrated
43、in accordance with the Annex of this test method.7.2 On-Site Data Acquisition Instruments, that may consistof a microphone with calibrator, a precision sound level metercapable of measuring average sound pressure level, a one-thirdoctave-band analyzer, and a strip chart recorder (optional). Testdata
44、 may be read on-site or tape recorded for later analysis.Recording instruments may consist of a microphone withcalibrator, precision sound level meter (optional), and aninstrument quality tape recorder. Laboratory data reductioninstruments may consist of a tape recorder, a one-third octave-band anal
45、yzer and a computer.7.3 The background noise of measuring instruments in eachone-third octave band must be at least 10 dB below measuredsound pressure levels.8. Test Signal8.1 The test signal shall be contiguous, one-third octavebands of pink or white noise, from 200 to 5000 Hz, and may beextended.9
46、. Speech Spectra9.1 The normal voice effort spectrum (2) of speech peaksgiven in Table 1 shall be used for the calculations. Additionally,other spectra may be used such as the raised voice spectrum ofspeech peaks in Table 1.10. Procedure10.1 Measurement Location:10.1.1 Select a listener (measurement
47、) location at the typi-cal ear-height of a seated listener, that is, the microphone shallbe located 1.2 m (4 ft) above the floor.10.1.2 The measurement location should be at least 1 m (3.3ft) from any vertical surfaces such as walls, columns, desks, oroffice furniture. In the event that this cannot
48、be met, theselected location shall be at the usual workers position.10.2 Ambient Measurements:10.2.1 With the test signal off, the average sound pressurelevel shall be measured in each one-third octave band over atime period of at least4satfour positions at 90 intervalsaround a circle of 0.3-m (1-ft
49、) radius centered on the location.The arithmetic mean sound pressure level shall be calculatedfor each band from the four measured values. The A-weightedsound level shall also be measured and calculated in thismanner. All data shall be obtained with the microphonediaphragm parallel to the floor and facing upwards.10.2.2 Verify that the measured ambient sound pressurelevels exceed the background noise of the instruments by atleast 10 dB in each band. If not, the data shall not be used.10.3 Source Location and Orientation:10.3.1 The sound source shall be placed at the talkerloc
