ANSI AMCA 300-2014 Reverberant Room Methods for Sound Testing of Fans.pdf

1、The International Authority on Air System ComponentsAIR MOVEMENT AND CONTROL ASSOCIATION INTERNATIONAL INC.ANSI/AMCA Standard 300-14Reverberant Room Method forSound Testing of FansAn American National Standard Approved by ANSI on August 14, 2014AIR MOVEMENT AND CONTROLASSOCIATION INTERNATIONAL, INC.

2、30 West University DriveArlington Heights, IL 60004-1893 U.S.A.Tel: (847) 394-0150 Fax: (847) 253-0088 Email : infoamca.org Web: www.amca.orgThe Air Movement and Control Association International Inc. is a not-for-profit international association of the worlds manufacturers of related air system equ

3、ipment, primarily but not limited to fans, louvers, dampers, air curtains, airflow measurement stations, acoustic attenuators and other air system components for the industrial, commercial and residential markets.ANSI/AMCA Standard 300-14Reverberant Room Methodsfor Sound Testing of FansAir Movement

4、and Control Association International30 W. University DriveArlington Heights, Illinois60004AMCA Standard 300-14 was adopted by the membership of the Air Movement and Control Association International Inc. on August 21, 2014. It was approved by the American National Standards Institute on August 14,

5、2014. 2005 by Air Movement and Control Association International Inc.All rights reserved. Reproduction or translation of any part of this work beyond that permitted by Sections 107 and 108 of the United States Copyright Act without the permission of the copyright owner is unlawful. Requests for perm

6、ission or further information should be addressed to the executive director, Air Movement and Control Association International Inc. at 30 West University Drive, Arlington Heights, IL 60004-1893 U.S.A.Air Movement and Control Association International Inc. will consider and decide all written compla

7、ints regarding its standards, certification programs, or interpretations thereof. For information on procedures for submitting and handling complaints, write to:Air Movement and Control Association International30 West University DriveArlington Heights, IL 60004-1893 U.S.A.European AMCAAvenue des Ar

8、ts, numro 46 Bruxelles (1000 Bruxelles)Asia AMCA Sdn BhdNo. 7, Jalan SiLC 1/6,Kawasan Perindustrian SiLC Nusajaya,Mukim Jelutong, 79200 Nusajaya, JohorMalaysiaAMCA uses its best efforts to produce standards for the benefit of the industry and the public in light of avail-able information and accepte

9、d industry practices. However, AMCA does not guarantee, certify or assure the safety or performance of any products, components or systems tested, designed, installed or operated in accordance with AMCA standards or that any tests conducted under its standards will be non-hazardous or free from risk

10、.AMCA PublicationsAuthorityCopyrightObjectionsDisclaimerReview CommitteeDavid Johnson Berner International CorporationCommittee ChairJohn Cermak Acme Engineering it may also conform to air test chamber conditions given in ANSI/AMCA Standard 210 1.3.1.3 Decibel (dB)A dimensionless unit of level in lo

11、garithmic terms for express-ing the ratio of a power or power-like quantity to a similar reference quantity (see Sections 3.1.13 and 3.1.14).3.1.4 Ducted fanA fan having a duct connected to either its inlet, its outlet or to both.3.1.5 End reflectionA phenomenon that occurs whenever sound is transmi

12、tted across an abrupt change in area, such as at the end of a duct in a room. When end reflection occurs, some of the sound entering the room is reflected back into the duct and does not escape into the room. 3.1.6 FrequencyThe number of times in one second that a periodic function repeats itself.3.

13、1.7 InformativeA term that indicates that the referenced material is provided as advice to the reader but does not constitute a mandatory requirement.3.1.8 Non-ducted fanA fan without ducts connected to its inlet and outlet.3.1.9 NormativeA term that indicates that the referenced material, if applie

14、d, constitutes a mandatory requirement.3.1.10 Octave bandThe interval between any two frequencies having a ratio of two. Fan sound power levels are reported in eight stan-dardized octave bands, shown in Table 2. Fan sound power levels may also be reported in one-third octave bands, also shown in Tab

15、le 2.3.1.11 Reverberant roomAn enclosure meeting the requirements of Annex A or Annex A and B.3.1.12 Shall and shouldThe word “shall” is to be understood as mandatory; the word “should” is to be understood as advisory.3.1.13 Sound power levelExpressed in decibels (dB), the value of 10 times the loga

16、-rithm (base 10) of the ratio of the sound power W to the reference sound power Wref, according to:LW, in dB = 10 log10( W/Wref) Eq. 3.2-13.1.14 Sound pressure levelExpressed in decibels (dB), the value of 20 times the loga-rithm (base 10) of the ratio of the sound pressure p to the reference sound

17、pressure pref, according to:Lp, in dB = 20 log10( p/pref) Eq. 3.2-22 | ANSI/AMCA 300-143.1.15 WavelengthThe distance between two points having the same phase in two consecutive cycles of a periodic wave, along a line in the direction of propagation 2. Wavelength () is determined by frequency and the

18、 speed of sound in the air through which the wave propagates:g = c/f Eq. 3.2-3Where:f = frequency, Hzc = 343 m/s at 20C (1125 ft/s at 68F)The value for c is acceptable for use in this standard within the limits of 5C (9F) for standard air.3.1.16 Standard airAir having a density of 1.2 kg/m3(0.075 lb

19、m/ft3). Standard air has a ratio of specific heats of 1.4 and a viscosity of 1.8185 10-3Pas (1.222 10-5lbm/ft-s). Air at 20C (68F), 50% rela-tive humidity and 101.325 kPa (14.696 lbm/in.2, 29.92 in. Hg) barometric pressure has these properties, approximately.3.2 Symbols and SubscriptsSee Table 1.4.

20、Instruments/Methods of Measurement4.1 Sound level meterThe sound level meter shall meet the requirements of ANSI S1.4 and S1.4A 3. It should be capable of accepting a microphone extension cable.4.2 Microphone systemA diffuse field microphone shall be used. The microphone system (transducer and any a

21、ssociated components and cable) shall meet the requirements for use in a Type 1 preci-sion sound level meter, according to ANSI S1.4 and S1.4A. A microphone with a nominal diameter of 13 mm (0.5 in.) is recommended.4.3 Frequency analyzer and weighting systemAn octave band or one-third octave band fi

22、lter set is required and shall meet the Order 3 Type 3-D requirements of ANSI S1.11 4. An A-weighting network shall meet the require-ments of ANSI S1.4 and S1.4A. Other weighting networks may be used to improve the accuracy, as outlined in Annex F.4.4 Data recording equipmentThis standard does not a

23、ttempt to set limitations on data recording equipment. Considerations include long-term stability, ease of use and the method of averaging the sound pressure signal. Modern integrating-type analyzers that comply with IEC 804 5 are recommended because they produce Lpvalues, eliminating any need for v

24、isual averag-ing. Graphic level recorders can be used to make permanent records and ease the problem of making visual averages from sound level meter indications. Octave BandsBand no. 1 2 3 4 5 6 7 8ANSI band no. 18 21 24 27 30 33 36 39Center frequency f, Hz 63 125 250 500 1000 2000 4000 8000Table 2

25、Standardized Octave and One-Third Bands (From ANSI S1.6 6)One-Third Octave BandsBand 1 Band 2 Band 3 Band 4ANSI band no. 17 18 19 20 21 22 23 24 25 26 27 28Center freq. f, Hz 50 63 80 100 125 160 200 250 315 400 500 630Band 5 Band 6 Band 7 Band 8ANSI band no. 29 30 31 32 33 34 35 36 37 38 39 40Cente

26、r freq. f, Hz 800 1000 1250 1600 2000 2500 3150 4000 5000 6300 8000 10000ANSI/AMCA 300-14 | 3Table 1 Symbols and SubscriptsSymbol Description SI Unit I-P UnitAminMinimum distance to reverberant field m ftc Speed of sound m/s ft/sD Duct diameter m ftEoEnd reflection factor at duct outlet dB dBEiEnd r

27、eflection factor at duct inlet dB dBEWEnd reflection factor, adjustment to sound power level dB dBf Frequency Hz HzJ1Bessel function of the first kind, first order - -k Wave number - -LpSound pressure level, re 20 Pa (0.0002 bar) dB dBLpcCorrected fan sound pressure level dB dBLpbSound pressure leve

28、l of room background measured over thenormal microphone path dB dBLpmSound pressure level of fan + room background measuredover the normal microphone path dB dBLpqSound pressure level of the RSS, corrected dB dBLpqmSound pressure level of RSS + room background measuredover the normal microphone path

29、 dB dBLWSound power level re 1 picowatt (1.0 10-12W) dB dBLWiSound power level transmitted to inlet duct from fan dB dBLWmiSound power level measured at the open inlet of the fan dB dBLWmoSound power level measured at the open outlet of the fan dB dBLWmtSound power level measured at the open inlet a

30、nd outlet of the fanLWoSound power level transmitted to the outlet duct from fan dB dBLWrSound power level of RSS dB dBp Sound pressure Pa barprefSound pressure reference level, 20 Pa (0.0002 bar) Pa barPsFan static pressure Pa in. wgPtFan total pressure Pa in. wgr Ratio (of duct area/orifice area)

31、dimensionless - -R Reflection coefficient dimensionless - -s Standard deviation dB dBW Sound power (in watts) W WWrefReference sound power (1 picowatt) W WZMMechanical impedance Ns/m -a Ratio of transmitted to reflected sound dimensionlessg Ratio of specific heats dimensionless Wavelength m ft Angul

32、ar frequency rad/s rad/s4 | ANSI/AMCA 300-144.5 Reference sound source (RSS)The reference sound source (RSS) should comply with the requirements of ANSI S12.5 7.4.5.1The RSS shall be a small, modified, direct-driven centrifugal fan having maximum overall dimensions of 610 mm (2 ft).4.5.2The RSS shal

33、l produce steady broad-band sound over at least the frequency range of 50 Hz to 10000 Hz. It shall comply in all respects with the performance requirements of ANSI S12.5.4.5.3The RSS shall be equipped with vibration isolators that mini-mize transmitted vibration. The degree of isolation should be 20

34、 dB or more. If metal springs are used as vibration isola-tors, rubber pads shall be used between the isolator and the structure of the reverberant room.4.5.4To ensure compliance with the stability requirements of ANSI S12.5, all operating parts of the RSS shall be rigidly and permanently attached.

35、No rubbing or wearing parts shall be permitted except lubricated bearings, and protection shall be provided against corrosion.4.5.5The RSS calibration shall consist of a determination of the sound power level of the RSS, including vibration isolators, when it is in operation on a reflecting plane ra

36、diating sound into a free field above that plane. The calibration shall be in accordance with ANSI S12.5 or as provided in Annex D. The maximum time interval since calibration shall not exceed that specified by the manufacturer or three years, whichever is shorter.4.6 Test methodThe test method is b

37、ased on an RSS substitution for the determination of sound power.Application of the test method requires that the test subject fan be set in position in a test room that is qualified accord-ing to the requirements of Section 5.1.Once the test room has been qualified, sound pressure levels are record

38、ed while the RSS operates. The fan is then operated, without the RSS in operation, at various perfor-mance points of interest for the given test speed, and the sound pressure levels are recorded. Since the sound power levels of the RSS are known, the substitution method is used to determine the soun

39、d power levels of the fan for each operating point.Current ANSI and ASA documents on sound testing, facili-ties and equipment are useful references. See Annex H.4.7 Accuracy of resultsAccuracy of test results is addressed in Annex C and depends upon several variables, including the room qualifi-cati

40、on and the type of test setup utilized.5. Equipment/Setups5.1 Reverberant roomAn enclosure meeting the requirements of Annex A is mandatory for the purposes of this standard. An enclosure meeting the requirements of Annex B is recommended for broad-band sound testing and is mandatory for the purpose

41、 of investigating pure tones and narrow bands.5.2 Setup categoriesA number of specific fan test setups are allowed. The test setups are determined by the airflow direction and the particular mounting arrangement of the test subject. The test setups fall into two general categories.The first category

42、 is for a free-standing unit that would be placed entirely in the test room (see Figure 1). Results of this arrangement yield total sound power LWmtof the test subject, non-ducted.The second category includes those fans that would be tested on a chamber or two-room system where only the inlet or out

43、let terminate in the test room (see Figures 2 and 3). These arrangements result in the determination of inlet (LWi) or outlet (LWo) sound power. Section 5.6 discusses the limitations that must be imposed on the test room for deter-mining the position of the test subject and the location of the micro

44、phone. The choice of test setup for a specific test will depend on the way the fan is expected to be applied in the field.5.3 Aerodynamic performanceAn aerodynamic performance test is necessary to determine the point of operation of a test subject. The test shall be performed in accordance with ANSI

45、/AMCA Standard 210 or other fan aerodynamic performance test standard having a demonstrated accuracy equivalent to ANSI/AMCA Standard 210.ANSI/AMCA 300-14 | 55.4 Mounting methodsThe method of mounting a test subject, connecting it to a non-integral driver or connecting it to an airflow test facility

46、 is not specified. Any conventional method may be used, includ-ing vibration isolation devices and short flexible connectors. Other than these, sound and vibration absorptive material may not be incorporated in the test subject unless it is a standard part of the fan. Ducts shall be of metal or othe

47、r rigid, dense, non-absorptive material and have no exposed sound absorption material on the interior or exterior surfaces.The driving motor and drive, when not an integral part of the test subject, may be damped or enclosed in any manner that does not expose sound absorption material to the test ro

48、om. When a driving motor and drive are an integral part of the test subject, they may not be treated in any manner, and normal belt tensions, bearings and lubricants shall be used. When a fan and its drive are both in the reverberant room, the test results may contain sound contributions from flanki

49、ng paths as well as mechanical and/or electrical sound from the drive system.5.5 Duct lengthOn a chamber or two-room setup, the length of duct shall be consistent with the acceptable practice per ANSI/AMCA Standard 210 necessary to accurately establish the point of rating.The length of duct shown in Figures 2 and 3 is consistent with the procedures of ANSI/AMCA Standard 210. Care must be exercised to ensure that no duct resonances exist in close proximity to specific frequencies of interest such as the blade passage frequency.5.6