ANSI AMCA 301-2014 Methods for Calculating Fan Sound Ratings From Laboratory Test Data.pdf

1、AIR MOVEMENT AND CONTROLASSOCIATION INTERNATIONAL, INC.30 West University DriveArlington Heights, IL 60004-1893 U.S.A.Email : infoamca.org Web: www.amca.orgTel: (847) 394-0150 Fax: (847) 253-0088The Air Movement and Control Association International Inc. is a not-for-profit international association

2、 of the worlds manufacturers of related air system equipment, 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.The International Authority on Ai

3、r System ComponentsAIR MOVEMENT AND CONTROL ASSOCIATION INTERNATIONAL INC.ANSI/AMCA Standard 301-14Methods for Calculating Fan Sound Ratings From Laboratory Test DataAn American National Standard Approved by ANSI on August 14, 2014ANSI/AMCA Standard 301-14Methods for CalculatingFan Sound Ratings fro

4、m Laboratory Test DataAir Movement and Control Association International30 W. University DriveArlington Heights, Illinois60004AMCA Standard 301-14 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

5、 Standards Institute on August 14, 2014. 2014 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 o

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7、sider and decide all written complaints 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 60004-18

8、93 U.S.A.European AMCAAvenue des Arts, 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

9、 avail-able information and accepted 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

10、 be non-hazardous or free from risk.AMCA PublicationsAuthorityCopyrightObjectionsDisclaimerTim Mathson Greenheck Fan CorporationCommittee ChairJohn Cermak Acme Engineering & Manufacturing CorporationKim Osborn Governair LLCTom Gustafson Hartzell Air MovementJohn Murphy JOGRAM Inc.Mike Brendel Lau In

11、dustries Inc.Bob Valbracht Loren Cook CompanyJeff Galinowski The New York Blower CompanyBrian Reynolds TraneRad Ganesh Twin City Fan Companies Ltd.Tim Orris AMCA StaffReview CommitteeRelated AMCA DocumentsAMCA Publication 11 Certified Ratings Program Operating ManualAMCA Publication 311 Certified Ra

12、tings Program Product Rating Manual for Fan Sound PerformanceANSI/AMCA Standard 300 Reverberant Room Method for Sound Testing of FansANSI/AMCA Standard 320 Laboratory Methods of Sound Testing of Fans Using Sound IntensityRelatedPublicationsRelatedStandards1. Purpose .12. Scope.13. Symbols and Subscr

13、ipts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14. Calculation of Sound Power Ratings .14.1 General .14.2 Reduction of sound power data to reference values .14.3 Calculation of reduced sound p

14、ower at a new point of operation .44.4 Conversion of reduced sound spectrum to sound power54.5 Effect of air density.55. Method of Calculating Sound Ratings in LWA, Sound Power Levels A-Weighted.56. Method of Calculating Sound Ratings in Sones 66.1 Sone6Annex A Recommended Test Sizes, Speeds and Ope

15、rating Points (Informative) .13Annex B Logarithmic Addition of One-Third Octave Bands (Informative) .14Annex C Presentation of Fan Sound Ratings (Normative) 15Annex D Procedure for Calculating Sound Power Ratings from Test Results (Normative)16Annex E Non-Geometrically-Similar Fans (Informative) 17C

16、ontentsANSI/AMCA 301-14 | 1Methods for CalculatingFan Sound Ratings from Laboratory Test Data1. PurposeThis document establishes standard methods for calculating fan sound ratings from laboratory test data.2. ScopeThis standard applies to any fan, if a test standard exists to measure its fan sound p

17、ower levels.3. Symbols and SubscriptsSee Table 2.4. Calculation of Sound Power Ratings4.1 GeneralSound generated by a fan has a variety of sources. These include aerodynamic and mechanical vibration as well as electrical sources that determine the overall acoustic perfor-mance of the fan. Sound powe

18、r level is the established metric for quantifying sound generated by fans. Test stan-dards such as ANSI/AMCA Standard 300, ANSI/AMCA Standard 320 and ISO 5136 describe procedures to test and measure sound power on a fan.It is desirable to report fan sound power levels across the entire fan performan

19、ce envelope. However, practical limi-tations of test laboratory capability and large data require-ments, often limit the number of tested sizes, speeds and points of operation. Fan laws for fan sound performance are not as reliable as the familiar fan laws for fan aerodynamic performance, nor are th

20、ey universally accepted. It is for this reason that sound power ratings are calculated largely by interpolation of available data. This section describes meth-ods for calculating the sound power ratings from base tests.The basic building blocks for these calculations are the sound power data for a g

21、iven fan operating at a constant speed. Sound power spectra, in the form of one-third octave or full octave band data, shall be available for at least three points over the usable portion of the air performance curve. Each of these spectra are referred to as determinations. These determinations are

22、used to calculate sound power levels at other points of rating.The base test determinations are chosen on either side of the rated point of operation. The preferable quantity used as the basis for interpolating the point of operation is the system resistance parameter, but airflow or pressure is als

23、o acceptable. For the general case where both the diameter and speed are changed, a diameter-independent variable must be used (see Table 1).Table 1Quantities, Variables and Diameter-Independent VariablesQuantity Variable Diameter-Independent VariableAirflow Q % QmaxPressure P % PmaxSystem Resistanc

24、e Parameter KPQ=2KPQDD=24Note: P can be either fan static (Ps) or fan total pressure (Pt)Base test data may not be available at the extreme points of operation, i.e., wide open delivery, where the sound power levels are usually highest. If the required point of operation is outside the range of dete

25、rminations tested, extrapolation can be used, but only if the resulting sound power level (LW) is equal to or higher than the value calculated from the near-est determination. If the result of extrapolation for any of the sound power levels is below that of the nearest determina-tion, the value from

26、 the nearest determination shall be used.Sound determinations may be available at multiple speeds and fan sizes. These additional data, especially at multiple speeds, can greatly enhance the accuracy of the methods described in the following procedure. Calculation of sound power levels from these da

27、ta to other points of rating follow a number of different procedures, depending on the extent of available sound power data. The procedures involve a variety of interpolation techniques and the application of fan scaling laws.In order to improve the accuracy of the sound power predic-tion, it is rec

28、ommended that calculations be performed using one-third octave band data as opposed to full octave band data.4.2 Reduction of sound power data to reference valuesTraditional sound power scaling methods begin with normal-izing or reducing sound power spectra to reference values at reduced frequencies

29、. This is done to conserve computa-2 | ANSI/AMCA 301-14Table 2Symbols and SubscriptsSymbols Description SI Units I-P UnitsD Impeller diameter mm in.f Frequency Hz HzfbpBlade pass frequency Hz HzfbwBandwidth Hz HzK System Resistance Parameter Pa/(m3/s)2(in. wg)/cfm2KDSystem Resistance Parameter Pa/(m

30、3/s)2mm4(in. wg)/cfm2in.4LpSound pressure level (re 2.0 10-5Pa) dB dBLWSound power level (re 1.0 10-12W) dB dBLWA Sound power level, A-weighted (re 1.0 10-12W) dB dBLWGGeneralized sound power level (re 1.0 10-12W) dB dBLWiSound power level at the inlet (re 1.0 10-12W) dB dBLWiA Sound power level at

31、the inlet, A-weighted dB dBLWmiMeasured sound power level from the inlet dB dBLWKSpecific sound power level (re 1.0 10-12W) dB dBLWFCapacity factor (re 1.0 10-12W) dB dBLWmoMeasured sound power level from the outlet dB dBLWoA Sound power level at outlet, A-weighted dB dBN Speed of rotation rpm rpmPs

32、Fan static pressure Pa in. wgPtFan total pressure Pa in. wgPvFan velocity pressure Pa in. wgQ Fan airflow rate m3/s cfmS Total loudness index sone sones Octave band loudness index sone sonesmMaximum octave band loudness index sone soneX Reduced frequency dimensionlessQmax Maximum fan airflow rate m3

33、/s cfmPmax Maximum fan static pressure or fan total pressure Pa in. wgb Slope of extrapolated line for reduced frequencies dimensionless(for frequencies greater than those tested) Test density kg/m3 lbm/ft3Subscript Descriptionc Converted or desired variable (i.e. Xc, Nc, dc, Qc, etc.)R, ref Referen

34、ce valuesANSI/AMCA 301-14 | 3tional resources that in the past involved graphical layouts, slide rule calculations or relatively slow electronic compu-tations. Modern computers have effectively eliminated the need to convert sound power to reference values. However, for historical consistency, the r

35、eduction to reference values is described in this standard. The reader should note that the reduced values are not a necessarily part of the proce-dure and can be avoided in a computer implementation of the method.One of two reduction methods can be used. The first, called the generalized sound powe

36、r method (see Section 4.2.1), reduces the sound power data to a reference speed and diameter. The second is the specific sound power method (see Section 4.2.2), which reduces the sound power to unit flow rate and unit fan total pressure. The aerodynamic fan laws can be used to show that the two meth

37、ods produce the same results.The first step utilizing either of these approaches is to reduce the available sound power data to the reference values. All subsequent calculations will begin with these values.4.2.1 Generalized sound powerThe generalized sound power for each frequency band shall be cal

38、culated by the following:LLNNDDWG WRR=50 70loglogEq. 4.1Where:N = fan speedD = impeller diameterThe reference values NRand DRcan be any value but have traditionally been 1000 rpm and 508 mm (20 in.), respectively.4.2.2 Specific sound powerThe specific sound power for each frequency band shall be cal

39、culated by the following:LLQQPPWK WRttR=10 20loglogEq. 4.2Where:Q = flow ratePt= fan total pressureThe reference values for flow rate (QR) and fan total pres-sure (PtR) can be any value but have traditionally been unit values in I-P units or 0.000472 m3/s (1 cfm) and 249 Pa (1 in. wg), respectively.

40、4.2.3 Reduced frequencyIn addition to reduced sound power values, the band frequencies are reduced by the fan speed. The reduced frequency for each band shall be calculated by the following:XfN=+10 20logEq. 4.3Where:f = band center frequencyN = fan speedSee Table 3 for center frequencies.Reduced sou

41、nd power data is often required outside the range of tested frequencies. In order to cover this range, the reduced sound power spectrum is extended on either end (see Figure 1). For reduced frequencies lower than those tested, the reduced sound power at the lowest reduced frequency shall be used. Fo

42、r reduced frequencies greater than those tested, the reduced sound power levels shall be extrapolated along a line passing through the highest frequency point. The slope of this line, b, is established by the highest two full octave bands or through linear regres-sion of the highest six one-third oc

43、tave bands.For full octaves:bLLXX=()()WK,G WK,G8787Eq. 4.4For one-third octaves:bXXLLXXii=()()()=iWK,GWK,Gii192421924Eq. 4.5The calculations described above are repeated for each sound power determination to form the reduced sound power and reduced frequencies. Subsequent calculations to other point

44、s of rating will use these reduced sound power spectra. It may therefore be desirable to store or publish these reduced sound power spectra instead of the original sound power levels.4.2.4 Conversion of reduced spectra to rated speedThe reduced sound power spectra from the base tests at each of the

45、required determinations are converted to the rated values of Xc, where:XfNcc=+10 20logEq. 4.64 | ANSI/AMCA 301-14for the center frequencies of each band. The values of LWGcor LWKcare either read off the graph as in Figure 2 or simply interpolated to the new values of Xc. Since fan sound often contai

46、ns a tone at the blade pass frequency (fbp), a correction must be made to account for the full value of this tone. The blade pass frequency is calcu-lated using the following formula:fNbp(Hz)Number of blades=60Eq. 4.7In the frequency band that contains the blade pass frequency of the rated fan, the

47、reduced sound power level (LWGcor LWKc) is compared to the value (LWGor LWK) at the base test blade pass frequency. If the value at the original blade pass frequency is higher, this value is used (see Figure 2).4.3 Calculation of reduced sound power at a new point of operationCalculation of the soun

48、d power at a new point of rating begins with the reduced sound power and reduced frequency data.The methods described here consider several basic scenarios:1. Reduced sound power calculated from determinations obtained at a single speed.2. Reduced sound power calculated at a speed that is bounded by

49、 two tested speeds.3. Reduced sound power calculated from tests of a smaller diameter fan.Various forms of interpolation and extrapolation are performed on each value of the reduced sound power spec-trum. First, the reduced sound power spectra are calculated for the rated values of Xcas in Section 4.2.4. This step accounts for the shift in frequency content with fan speed. Next, these reduced sound spectra for surrounding deter-minations