1、 i 2012 Standard for Sound Rating of Ducted Air Moving and Conditioning Equipment Approved by ANSI on June 26, 2013 ANSI/AHRI Standard 261 (SI) Price $15.00 (M) $30.00 (NM) Copyright 2012, by Air-Conditioning, Heating and Refrigeration Institute Printed in U.S.A. Registered United States Patent and
2、Trademark Office IMPORTANT SAFETY DISCLAIMER AHRI does not set safety standards and does not certify or guarantee the safety of any products, components or systems designed, tested, rated, installed or operated in accordance with this standard/guideline. It is strongly recommended that products be d
3、esigned, constructed, assembled, installed and operated in accordance with nationally recognized safety standards and code requirements appropriate for products covered by this standard/guideline. AHRI uses its best efforts to develop standards/guidelines employing state-of-the-art and accepted indu
4、stry practices. AHRI does not certify or guarantee that any tests conducted under its standards/guidelines will be non-hazardous or free from risk. Note: This standard supersedes AHRI Standard 260-2001 and differs in the following ways. Data in the 63 Hertz Octave Band is required; Sound power shall
5、 be determined following AHRI Standard 220 procedures if a reverberation room is used; Sound power shall be determined following ISO 9614 procedures if Sound Intensity is used; The Duct End Correction shall be determined following ASHRAE Technical Report 1314; Acoustic Test Elbow corrections shall f
6、ollow the method described by Beranek (1960). TABLE OF CONTENTS SECTION PAGE Section 1. Purpose . .1 Section 2. Scope .4 Section 3. Definitions. 4 Section 4. Requirements for Acquiring Sound Data. . 7 Section 5. Sound Level Calculations 15 Section 6. Equipment Sound Ratings. 17 Section 7. Conformanc
7、e Conditions 20 TABLES Table 1. Reproducibility in the Determination of Ducted Equipment Sound Power Levels . 14 FIGURES Figure 1. Typical Ducted Product Application 2 Figure 2. Relationship Between Sound Components and Sound Sources .3 Figure 3. Concept Reverberation Room Ducted Discharge Test Set-
8、up 9 Figure 4. Concept Sound Intensity Ducted Discharge Test Set-up. .9 Figure 5. Concept Reverberation Room Ducted Inlet Test Set-up. 9 Figure 6. Concept Sound Intensity Ducted Inlet Test Set-up. 10 Figure 7. Concept Reverberation Room Casing Radiated Test Set-up .10 Figure 8. Concept Sound Intensi
9、ty Casing Radiated Test Set-up .10 Figure 9. Concept Reverberation Room Free Discharge (or Inlet) Combined with Casing Radiated Test Set-up 11 Figure 10.Concept Sound Intensity Free Discharge (or Inlet) Combined with Casing Radiated Test Set-up 11 Figure 11. Concept Reverberation Room Free Discharge
10、 (or Inlet) Set-up .12 Figure 12. Concept Sound Intensity Free Discharge (or Inlet) Test Set-up12 APPENDICES Appendix A. References Normative .21 Appendix B. References - Informative 22 Appendix C. Acoustic Test Elbow Correction (E2) - Normative 23 Appendix D. Effects of Other Sources - Normative 25
11、 Appendix E. Supply Fan Modulation Device Effects - Normative .27 Appendix F. Determination of Sound Power Using Sound Intensity - Normative. 28 TABLES FOR APPENDICES Table C.1 Insertion Loss of Unlined Elbows.23 Table C.2 Examples of Test Elbow Insertion Loss, dB .24 Table F.1 Performance Verificat
12、ion Limits .30 Table F.2 Convergence Index 31 FIGURES FOR APPENDICES Figure C.1 Insertion Loss of Unlined Acoustic Test Duct Elbows. 23 Figure F.1 Performance Verification by Comparison with a Reference Sound Source Set-up. 30 ANSI/AHRI STANDARD 261 (SI)-2012_ 1 SOUND RATING OF DUCTED AIR MOVING AND
13、 CONDITIONING EQUIPMENT Section 1. Purpose 1.1 Purpose. The purpose of this standard is to establish a method of sound rating the indoor portions of ducted air moving and conditioning equipment. The standard provides definitions; requirements for acquiring mapped sound data; sound power level calcul
14、ations and ratings; minimum data requirements for published sound ratings; and conformance conditions. 1.1.1 Intent. This standard is intended for the guidance of the industry, including manufacturers, engineers, installers, contractors and users. 1.1.2 Review and Amendment. This standard is subject
15、 to review and amendment as technology advances. 1.2 Rationale. Ducted Equipment presents unique challenges when providing sound ratings since their ratings are used to both compare products and to provide the information necessary to predict application sound levels. For these reasons, the sound ra
16、tings shall define the sound coming from various portions of the equipment (Sound Components). The Sound Components are the Sound Sources that impact the application sound paths. Ducted air-conditioning equipment can have ducted discharge, ducted inlet, and casing radiated Sound Components. Dependin
17、g on its applied configuration, free discharge (or free inlet) combined with the casing radiated sound component may also be needed. All Sound Components are acoustically described/rated by utilizing a mapped sound rating approach that is typically referenced to the products supply fan operating map
18、. The supply fan is contained in the Base Unit of the product. In addition, this standard defines an approach to account for the acoustical effects of product Appurtenances (such as modulation devices or discharge/inlet plena) and other Sound Sources (such as the refrigeration circuit, return and ex
19、haust fans, etc.) to the Base Unit Mapped Sound Rating. Thus, a Mapped Sound Rating can be developed for a given product configuration and each of its various Sound Components defining the sound for any product operating condition. Figure 1 presents an example of a typical product application showin
20、g the relationship between the product Sound Components and the various application sound paths. Figure 2 presents an example of a typical vertically ducted product depicting the contribution of the various product Sound Sources on the Sound Components. All Sound Components are tested utilizing eith
21、er a reverberation room (qualified by test) or using Sound Intensity. Reverberation room tests are conducted using the Comparison Method and a calibrated Reference Sound Source, while the Sound Intensity tests are conducted using measurements made at discrete points or by the scanning method. Sound
22、ratings are in the form of Octave Band Sound Power Levels (dB) from 63 to 8000 Hz derived from One-third Octave Band measurements. In addition to the stated Octave Band ratings, this standard can be used to provide One-third Octave Band sound ratings from 50 to 10,000 Hz. _ANSI/AHRI STANDARD 261 (SI
23、)-2012 2 In the example presented in Figure 1, there are two Sound Components present, ducted discharge and free inlet combined with casing radiated. The ducted discharge sound component affects or defines the source strength for two application sound paths 1) the supply duct airborne sound and 2) t
24、he supply duct breakout sound. The free inlet combined with casing radiated sound component affects or defines the source strength for the 3) return airborne and 4) wall transmission application sound paths. Figure 1 Typical Ducted Product Application Typical ducted equipment Typical application sou
25、nd paths Ducted discharge sound component Free inlet combined with casing radiated sound component ANSI/AHRI STANDARD 261 (SI)-2012_ 3 In Figure 2, a typical vertical ducted unit is presented with its Sound Components and their contributing product Sound Sources. In this example, there are two Sound
26、 Components, the ducted discharge and the ducted inlet. The ducted discharge sound component is first defined by the supply fan discharge sound in the Base Unit coupled with the discharge plenum. The contribution of appurtenance sound from supply fan discharge airflow impinging the heat exchanger in
27、 the discharge plenum must also be added to the supply fan discharge sound. Finally, the effects of the other sources on the ducted discharge sound from the condenser fans and the refrigerant circuit must be considered. For the ducted inlet sound component, the sound from the return side of the retu
28、rn fan is first considered. In this case, the return side sound from the supply fan contributes as another sound source. Figure 2 Relationship Between Sound Components and Sound Sources _ANSI/AHRI STANDARD 261 (SI)-2012 4 Section 2. Scope 2.1 Scope. This standard applies to Ducted Equipment and spec
29、ifies the methods for the determination of the sound power rating of the indoor sections of factory-made residential, commercial and industrial air-conditioning and Heat Pump equipment, which are electrically driven, with mechanical compression and containing fans, using mapped sound data for rating
30、 the various product Sound Components. Sound power ratings reported are octave-band Sound Power Levels from 63 Hz to 8000 Hz. The terms Air-Conditioner and equipment are used to mean Air-Conditioners and Heat Pumps in this part of the standard. In addition to the stated Octave Band ratings, this sta
31、ndard can additionally be used to provide One-third Octave Band sound ratings from 50 to 10,000 Hz. Section 3. Definitions All terms in this document will follow the standard industry definitions in the ASHRAE Wikipedia website (http:/wiki.ashrae.org/index.php/ASHRAEwiki) unless otherwise defined in
32、 this section. 3.1 Acoustic Baffle. A barrier that creates a well defined duct termination and test surface for a ducted sound intensity measurement. The barrier is rigid and non-absorbing. 3.2 Acoustic Test Duct. A duct used to convey the sound of the unit configuration under test to the reverberat
33、ion room or intensity surface during a ducted discharge or ducted inlet sound component test. A Duct End Correction shall be added to the sound data measured in the reverberation room or from the intensity method to account for the presence of the duct termination. 3.3 Acoustic Test Duct Elbow. An e
34、lbow that may be added to the Acoustic Test Duct to facilitate testing. An Acoustic Test Duct Elbow Correction, shall be made (in addition to the Duct End Correction) to the sound data to account for the presence of the Acoustic Test Duct Elbow. 3.4 Acoustic Test Duct Elbow Correction (E2). A correc
35、tion in a frequency band to account for insertion loss effects of the elbow on the sound propagating through the Acoustic Test Duct. The table in Appendix C of this standard defines the Acoustic Test Duct Elbow Correction. 3.5 Appurtenance. An addition to a Base Unit for purposes of air modulation,
36、heat transfer, control, isolation, safety, static pressure regain, etc. Examples of Appurtenances include: 1. Coil(s) 2. Electric heater(s) 3. Air filter(s) 4. Damper(s) 5. Moisture eliminator(s) 6. Fan-motor drive(s) 7. Gas heat exchanger(s) 8. Inlet or discharge plena 9. Modulating device(s) in th
37、e fan inlet/discharge 10. Application duct geometry(s) (such as duct elbow configurations) 11. Alternate unit casing construction(s) (such as double walled, lined, perforated face) 3.6 Air-Conditioner. One or more factory-made assemblies which normally include an evaporator or cooling coil, a compre
38、ssor and condenser combination, and may include a heating function; where such equipment is provided in more than one assembly, the separated assemblies shall be designed to be used together. ANSI/AHRI STANDARD 261 (SI)-2012_ 5 3.7 Base Unit. A factory-made encased assembly consisting of one or more
39、 fans meant to be connected to a duct and other necessary equipment to perform one or more of the functions of circulating, cleaning, heating, cooling, humidifying, and mixing of air, but which may or may not include a source of heating or cooling. 3.8 Comparison Method. A method of determining Soun
40、d Power Level by comparing the average Sound Pressure Level produced in the room to a Reference Sound Source of known Sound Power Level output. The difference in Sound Power Level is equal to the difference in Sound Pressure Level when conditions in the room are the same for both sets of measurement
41、s. 3.9 Ducted Equipment. Heating, ventilating and air conditioning equipment having one or more supply fans which employ ductwork to convey the conditioned air to and/or from the desired space. Ducted Equipment may have various combinations of discharges and inlets as follows: 3.9.1 Ducted discharge
42、(s) and ducted inlet(s). 3.9.2 Ducted discharge(s) with free inlet(s). 3.9.3 Ducted inlet(s) with free discharge(s). This equipment may be ducted in various configurations horizontally and vertically, and may incorporate multiple inlets and outlets. 3.10 Duct End Correction (E1). A correction in a f
43、requency band that accounts for the acoustic energy in an Acoustic Test Duct that is prevented from entering the test space by the impedance mismatch created by the termination of the Acoustic Test Duct. A method for computing the Duct End Correction is described in Section 5.2.1 of this standard. 3
44、.11 Effective Diameter. The diameter of an Acoustic Test Duct which is equal to either the diameter of a circular duct or the Effective Diameter of a rectangular duct calculated according to Equation 1, m: 4A= De2/11 Where: A = Cross-sectional area of the duct, m2De= Effective Diameter, m 3.12 Heat
45、Pump. One or more factory-made assemblies which normally include an indoor conditioning coil, a compressor and outdoor heat exchanger (including means to provide a heating function), and may optionally include a cooling function. When such equipment is provided in more than one assembly, the separat
46、ed assemblies shall be designed to be used together. 3.13 Hertz (Hz). Unit of frequency in cycles per second. 3.14 Mapped Sound Rating. Equipment sound ratings that are based upon a series of tests performed across the range of operating conditions determined typically from a flow pressure map for t
47、he product supply fan and as defined by the equipment manufacturer. Contributions due to Appurtenances and other sources such as return fans, exhaust fans, and the refrigeration circuit are superimposed on the supply fan sound rating map. One-third Octave Band Sound Power Levels are obtained for each test point of the series to provide Octave Band sound power ratings. The mapped rating process is defined in Section 6.2. A special case exists when a supply fan is used in conjunction with a return or exhaust fan in the Base Unit (See
