AHRI 1120-2012 Acoustical Test Methods and Sound Power Rating Procedures for Transport Refrigeration Equipment.pdf

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1、 2012 Standard for Acoustical Test Methods and Sound Power Rating Procedures for Transport Refrigeration Equipment Approved by ANSI on 13 June 2011 Approved by ANSI on 13 June 2011 AHRI Standard 1120 Price $10.00 (M) $20.00 (NM) Copyright 2012, by Air-Conditioning Heating and Refrigeration Institute

2、 Printed in U.S.A. Registered United States Patent and Trademark Office IMPORTANT SAFETY RECOMMENDATIONS It is strongly recommended that the product be designed, constructed, assembled and installed in accordance with nationally recognized safety requirements appropriate for products covered by this

3、 standard. AHRI, as a manufacturers trade association, uses its best efforts to develop standards employing state-of-the-art and accepted industry practices. However, AHRI does not certify or guarantee safety of any products, components or systems designed, tested, rated, installed or operated in ac

4、cordance with these standards or that any tests conducted under its standards will be non-hazardous or free from risk. Note: This standards supersedes ANSI/AHRI Standard 1120-2007. TABLE OF CONTENTS SECTION PAGE Section 1. Purpose . 1 Section 2. Scope 1 Section 3 Definitions 1 Section 4. Requirement

5、s for Conducting Sound Tests 3 Section 5. Sound Rating Procedures . 4 Section 6. Minimum Data Requirements for Published Ratings . 6 Section 7. Conformance Conditions 7 TABLES Table 1. Standard Frequency Bands . 2 Table 2. A-weighted Conversions 5 APPENDICES Appendix A. References Normative . 8 Appe

6、ndix B. References Informative . 8 Appendix C. Special Rating Procedure Using ISO 9614 - Informative 9 Appendix D. Information to be Recorded - Normative . 10 Appendix E. Sound Pressure Measurement Method - Informative . 12 AHRI STANDARD 1120-2012 1 ACOUSTICAL TEST METHODS AND SOUND POWER RATING PRO

7、CEDURES FOR TRANSPORT REFRIGERATION EQUIPMENT Section 1. Purpose 1.1 Purpose. The purpose of this standard is to establish acoustical test methods for Transport Refrigeration Equipment and to provide definitions; test requirements; rating requirements; minimum data requirements for Published Ratings

8、; 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 to review and amendment as technology advances. Section 2. Scope 2.1 Sco

9、pe. This standard applies to factory-made Transport Refrigeration Equipment. Section 3. Definitions All terms in this document shall follow the standard industry definitions in the current edition of ASHRAE Terminology of Heating, Ventilation, Air-Conditioning, and Refrigeration unless otherwise def

10、ined in this section. 3.1 Transport Refrigeration Equipment. A combination of one or more factory-made assemblies, which may include a compressor, an internal combustion engine or electric motor, and condenser combination; an evaporator or air-cooler; all necessary refrigerant lines and electrical w

11、iring; and means whereby the unit can be suitably mounted and installed on a vehicle which it is intended to serve. Where such equipment is used in more than one assembly, the individual assemblies are designed to be used together, and the rating requirements outlined in this standard are based upon

12、 the use of matched assemblies. Examples of Transport Refrigeration Equipment include: 3.1.1 Truck Transport Refrigeration Unit. A refrigeration unit typically mounted above the truck cab on the front of an insulated box that is part of a unified chassis. Truck units may be autonomous or non-autonom

13、ous. Small non-autonomous truck units are often mounted to the roofs of vans or insulated boxes on small trucks. 3.1.2 Autonomous Transport Refrigeration Unit. Autonomous refrigeration equipment has its own power supply, most frequently a self-contained engine, and a means of moving refrigerant enab

14、ling it to control temperature without the support of a vehicle or electric power supply. 3.1.3 Container Transport Refrigeration Unit. Container units are non-autonomous electric refrigeration units comprising one end of insulated shipping containers that control temperature most frequently in ocea

15、n-going shipping containers. Power for container units is supplied by the electric mains in port, by the ship at sea, and by Gensets when the container is being moved by road or rail. 3.1.4 Cryogenic Transport Refrigeration Unit. Cryogenic units utilize the heat transfer from a cryogenic fluid flowi

16、ng through a coil in an insulated space to maintain temperature. These units can be autonomous if the energy of the fluid is used to power fans or non-autonomous when fans receive their power from the truck. 3.1.5 Eutectic Transport Refrigeration Unit. Temperature in the refrigerated space is mainta

17、ined at the designed melting temperature of an encased fluid lining the interior walls and/or ceiling of the insulated cargo space. A non-autonomous electric refrigeration unit is part of a eutectic system, which freezes the fluid while the vehicle is stationary and plugged into the electric mains.

18、Temperature control is available in eutectic units until the fluid has completely melted. Noise from a eutectic unit exists when the electric power is connected and the fluid is being frozen. AHRI STANDARD 1120-2012 2 3.1.6 Genset. In transport refrigeration applications, a Genset is comprised of an

19、 engine, a generator, and a fuel tank and is designed to supply electrical power to container units being transported over land on rail cars or trailers. Some Gensets mount to the container unit itself while others mount under the chassis carrying the container. 3.1.7 Non-autonomous Transport Refrig

20、eration Unit. Non-autonomous refrigeration equipment cannot operate without external power. Some non-autonomous equipment requires a truck engine to run the compressor that moves the refrigerant and/or a truck engine turning an alternator to supply electrical power. Other non-autonomous equipment re

21、quires power from the electric mains. 3.1.8 Trailer Transport Refrigeration Unit. A refrigeration unit mounted on the front of an insulated trailer. Fuel for trailer units is supplied from a tank mounted under the trailer enabling the unit to run independent of a tractor. Trailer units are autonomou

22、s equipment. 3.1.9 Undermount Transport Refrigeration Unit. Undermount units are designed to mount just below insulated boxes on a unified chassis as well as short trailers. Undermount units can be autonomous or non-autonomous. 3.2 Octave Band. A band of sound covering a range of frequencies such th

23、at the highest is twice the lowest, as used in this standard and shown in Table 1. Table 1. Standard Frequency Bands1 Octave Band One-third Octave Band Lower Frequency Limit, Hz Center Frequency, Hz2Upper Frequency Limit, Hz Lower Frequency Limit, Hz Center Frequency, Hz2Upper Frequency Limit, Hz 44

24、 90 180 355 710 1,400 2,800 5,600 633 125 250 500 1,000 2,000 4,000 8,000 90 180 355 710 1,400 2,800 5,600 11,200 44 56 71 90 112 140 180 224 280 355 450 560 710 900 1,120 1,400 1,800 2,240 2,800 3,550 4,500 5,600 7,100 9,000 503633803100 125 160 200 250 315 400 500 630 800 1,000 1,250 1,600 2,000 2

25、,500 3,150 4,000 5,000 6,300 8,000 10,000 56 71 90 112 140 180 224 280 355 450 560 710 900 1,120 1,400 1,800 2,240 2,800 3,550 4,500 5,600 7,100 9,000 11,200 Notes: 1. The frequencies have been rounded off to whole numbers. 2. The geometric mean of the frequency limits. 3. These bands are considered

26、 to be optional. AHRI STANDARD 1120-2012 3 3.3 One-third Octave Band. A band of sound covering a range of frequencies such that the highest frequency is the cube root of two times the lowest frequency. The One-third Octave Bands used in this standard are those defined in ANSI Standard S1.11. 3.4 Pub

27、lished Rating. A statement of the assigned values of those performance characteristics, under stated Rating Conditions, by which a unit may be chosen to fit its application. These values apply to all units of like nominal capacity and type (identification) produced by the same manufacturer. As used

28、herein, the term Published Rating includes the rating of all performance characteristics shown on the unit or published in specifications, advertising or other literature controlled by the manufacturer, at stated Rating Conditions. 3.4.1 Application Rating. A rating based on tests performed at appli

29、cation Rating Conditions (other than Standard Rating Conditions). 3.4.2 Standard Rating. A rating based on tests performed at Standard Rating Conditions. 3.5 Rating Conditions. Any set of operating conditions under which a single level of performance results and which causes only that level of perfo

30、rmance to occur. 3.5.1 Standard Rating Conditions. Rating Conditions used as the basis of comparison for performance characteristics. 3.6 “Shall“ or “Should“. “Shall“ or “should“ shall be interpreted as follows: 3.6.1 Shall. Where “shall“ or “shall not“ is used for a provision specified, that provis

31、ion is mandatory if compliance with the standard is claimed. 3.6.2 Should. “Should“ is used to indicate provisions which are not mandatory but which are desirable as good practice. 3.7 Sound Power Level, Lw. Ten times the logarithm to the base ten of the ratio of the sound power radiated by the sour

32、ce to a reference sound power, expressed in decibels, dB. The reference sound power used in this standard is 1 picowatt, pW. 3.7.1 A-weighted Sound Power Level, LwA. The logarithmic summation of A-weighted, one-third octave band Sound Power Levels. 3.8 Sound Pressure Level, LP. Twenty times the loga

33、rithm to the base ten of the ratio of a given sound pressure to a reference sound pressure of 20 Pa, dB. Section 4. Requirements for Conducting Sound Tests 4.1 Testing Requirements for Equipment. Sound tests shall be conducted in accordance with the test methods (Grade 1 or Grade 2 as identified in

34、ISO Standard 12001) specified in ANSI S12.51/ISO 3741, ISO Standards 3744, 3745, or 9614-Parts 1 or 2. The choice of a test method is left to the discretion of the user. 4.2 Data To Be Taken. Sound Power Levels, Lwshall be determined in decibels (ref. 1 pW) for the One-third Octave Bands from 100 to

35、 10,000 Hz or the full Octave Bands from 125 to 8,000 Hz as listed in Table 1. Alternatively, A-weighted Sound Power Levels, LwAcan be determined in decibels as an overall value. Sound Power Levels shall be determined in accordance with the specific ISO acoustic standard used to conduct the test (se

36、e Appendix A, Normative References). 4.3 Special Test Considerations 4.3.1 High air speeds from the unit under test may affect the sound measured by a microphone. These effects will tend to result in an overestimation of the sound power of the product. Thus, the air speed at the microphone shall not

37、 exceed 2 m/s. The error due to air-streams may be checked by repeating the measurement at a larger distance from the product. If the resulting Sound Power Levels at both measurement distances are within 1.0 dB, the air-stream effects are negligible. AHRI STANDARD 1120-2012 4 4.3.2 If testing is con

38、ducted in accordance with ISO Standard 9614, data is to be reported only for frequencies up to and including 6.3 kHz. Data above 6.3 kHz can only be provided for information purposes when using ISO Standard 9614 because the uncertainties are not defined above 6.3 kHz. In addition, special considerat

39、ion must be given to the determination of the overall A-weighted Sound Power Level rating from Section 5.4 using the procedures established in Appendix C. When testing to ISO Standard 9614, a larger microphone spacer will allow measurements at lower frequencies, but the field indicators of this stan

40、dard shall be satisfied. 4.3.3 When extending the testing procedures below 100 Hz while following ANSI S12.51/ISO 3741, the standard deviation shall not exceed 5 dB. Additionally, when information on Sound Power Levels in the 50, 63 and 80 Hz One-third Octave Bands or the 63 Hz Octave Band is to be

41、optionally provided, the standard rating temperature conditions and the measurement methods in the applicable standards shall be used. 4.3.4 When testing to ISO Standard 3744, the acoustical environment shall have an acoustical environmental correction K2of less than or equal to 2 dB. Additionally,

42、the hemispherical measurement grid shall be used. Use of the parallelepiped or conformal measurement grids when measuring transport refrigeration equipment sound typically produces inaccurate results and is therefore not allowed. 4.3.5 When testing to ISO Standard 3745, the acoustical environment sh

43、all have an acoustical environmental correction K2 of less than or equal to 0.5 dB. 4.4 Use of windscreens. The use of a foam windscreen on the microphone is required in these tests. The effect of the windscreen on the microphone response shall not be more than 1 dB for frequencies of 50 to 4,000 Hz

44、 or 1.5 dB for frequencies of 4 to 10 kHz. 4.5 Equipment Mounting. 4.5.1 All equipment is to be mounted according to the manufacturers installation instructions. If any deviations from these instructions are necessary, they must be made in a manner that will not affect the acoustic performance of th

45、e equipment and such mounting deviations shall be reported. Following these guidelines, it is permissible to mount the equipment on a fabricated support structure provided that said structure is representative of an actual installation and does not affect the acoustic performance of the equipment un

46、der test. For example, in all cases the bottom of the test unit shall be located no closer to the ground/floor than 0.5 m to insure that sound radiating from the bottom of the test unit is included in the measurement. When testing indoors, the use of ducts, hoses or other devices to remove exhaust g

47、ases shall not reduce or alter the characteristics of the exhaust sound. A description of the mounting structure shall be reported. Section 5. Sound Rating Procedures 5.1 General. Use of this standard results in a single number, A-weighted sound power level rating for the unit under test. One-third

48、octave band Sound Power Levels, octave band Sound Power Levels or calculated A-weighted Sound Power Levels may be used to obtain this rating. Sound ratings for each operating condition of interest shall be determined with the equipment under test operating in a fully loaded, pull down mode of operat

49、ion. Care must be exercised to ensure that there is a sufficient difference between the set point and the outdoor/box temperatures such that the unit under test does not cycle or unload during the test. 5.2 Determination of Equipment Sound Power Levels. Equipment Sound Power Levels for each Octave Band or One-third Octave Band shown in Table 1 shall be determined in accordance with Section 4. The Sound Power Levels shall be expressed in decibels (ref. 1 pW) for each Octave Band or One-third Octave Band. 5.3 Determination of the A-weighted Overall Sound Power Level Rating. The sin