AHRI 275-2010 Application of Outdoor Unitary Equipment A-Weighted Sound Power Ratings.pdf

1、 ANSI/AHRI STANDARD 275-2010 2010 Standard for Application of Outdoor Unitary EquipmentA-Weighted Sound Power Ratings Approved by ANSI on 4 January 2011 ANSI/AHRI Standard 275 ANSI/AHRI STANDARD 275-2010 IMPORTANT SAFETY RECOMMENDATIONS It is strongly recommended that the product be designed, constr

2、ucted, assembled and installed in accordance with nationally recognized safety requirements, appropriate for products covered by this standard. AHRI, as a manufacturers trade association, uses its best efforts to develop standards, employing state-of-the-art and accepted industry practices. However,

3、 AHRI does not certify or guarantee safety of any products, components or systems designed, tested, rated, installed or operated in accordance with these standards or that any test conducted under its standards will be non-hazardous or free from risk. Note: This Standard supersedes AHRI Standard 275

4、-2009. This version of the standard differs from that of 2009 in the following ways: The 2008 edition of AHRI Standard 270 is now used for the rating. Per AHRI Standard 270, the tone adjusted A-Weighted Sound Power Level has been replaced with an overall A-Weighted Sound Power Level. Note: Although

5、this standard is meant as an application for equipment rated per AHRI Standard 270, other standards that provide rating(s) similar to AHRI Standard 270 may be able to use the methodology, techniques and procedures described within this standard. 0 TABLE OF CONTENTS SECTION PAGE Section 1. Purpose .

6、1 Section 2. Scope 1 Section 3. Definitions 1 Section 4. Procedure for Estimating A-Weighted Sound Pressure Level(s) 2 Section 5. Voluntary Conformance12 TABLES Table 1. Application Factors for Estimating A-Weighted Sound Pressure Level(s) (Equipment Location Factor)3 Table 2. Application Factors fo

7、r Estimating A-Weighted Sound Pressure Level(s) (Barrier Shielding Factor)5 Table 3. Application Factors for Estimating A-Weighted Sound Pressure Level(s) (Sound Path Factor) 6 Table 4. Distance Factor.7 Table 5. Calculation Procedures for Estimating A-Weighted Sound Pressure Level. . 7 Table 6. Val

8、ues Used to Combine Sound Levels for Multi-Unit Installations.8 FIGURES Figure 1. Corner of Building.5 Figure 2. Corner of Flat Roof and Wall.5 Figure 3. Parapet around Flat Roof.6 Figure 4. Heavy Continuous Wall.6 Figure 5. Sound Paths According to Table 3.6 APPENDICES Appendix A. References Normat

9、ive13 Appendix B. References - Informative.13 Appendix C. Recommended Practices - Informative.14 ANSI/AHRI STANDARD 275-2010 1 APPLICATION OF OUTDOOR UNITARY EQUIPMENT A-WEIGHTED SOUND POWER RATINGS Section 1. Purpose 1.1 Purpose. The purpose of this standard is to establish for outdoor unitary equi

10、pment: definitions, procedures for estimating A-Weighted Sound Pressure Levels from the A-Weighted Sound Power Ratings, and recommended application practices. 1.1.1 Intent. This standard is intended for the guidance of the industry, including manufacturers, engineers, installers, contractors and use

11、rs. 1.1.2 Review and Amendment. This standard is subject to review and amendment as technology advances. Section 2. Scope 2.1 Scope. This standard applies to the outdoor sections of factory-made air-conditioning and heat pump equipment with cooling capacities up to 40kW, as in the scope of AHRI Stan

12、dards 210/240 and 340/360 when rated in accordance with AHRI Standard 270. Section 3. Definitions All terms in this document will follow the standard industry definitions established in the current edition of ASHRAE Terminology of Heating, Ventilation, Air Conditioning and Refrigeration, unless othe

13、rwise defined in this section. 3.1 Air-Source Unitary Heat Pump. One or more factory-made assemblies which normally include an indoor conditioning coil(s), compressor(s), and outdoor coil(s), including means to provide a heating function. When such equipment is provided in more than one assembly, th

14、e separated assemblies shall be designed to be used together, and the requirements of rating outlined in the standard are based upon the use of matched assemblies. 3.1.1 Functions. They shall provide the function of air heating with controlled temperature and may include the functions of air-cooling

15、, air-circulating, air-cleaning, dehumidifying or humidifying. 3.2 Published 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 size and

16、 type (identification) produced by the same manufacturer. As used 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.

17、2.1 Application Rating. A rating based on tests performed at application Rating Conditions (other than Standard Rating Conditions). 3.2.2 Standard Rating. A rating based on tests performed at Standard Rating Conditions. 3.3 Rating Conditions. Any set of operating conditions under which a single leve

18、l of performance results, and which cause only that level of performance to occur. 3.3.1 Standard Rating Conditions. Rating Conditions used as the basis of comparison for performance characteristics. ANSI/AHRI STANDARD 275-2010 2 3.4 “Shall,“ “Should,“ “Recommended,“ or “It Is Recommended.“ “Shall,“

19、 “should,“ “recommended,“ or “it is recommended“ shall be interpreted as follows: 3.4.1 Shall. Where “shall“ or “shall not“ is used for a provision specified, that provision is mandatory if compliance with the standard is claimed. 3.4.2 Should, Recommended, or It Is Recommended. “Should,“ “recommend

20、ed,“ or “it is recommended“ is used to indicate provisions which are not mandatory but which are desirable as good practice. 3.5 Sound Power Level, Lw. Ten times the logarithm to the base ten of the ratio of the sound power radiated by the source to a reference sound power, expressed in decibels (dB

21、). The reference sound power used in this standard is 1 picowatt (pW). 3.5.1 A-Weighted Sound Power Level, LwA. For the purposes of this standard it is the units AHRI 270 A-Weighted Sound Power Level Rating(s). 3.6 Sound Pressure Level, Lp. Twenty times the logarithm to the base ten of the ratio of

22、a given sound pressure to a reference sound pressure of 20 Pa, expressed in decibels (dB). 3.6.1 A-Weighted Sound Pressure Level LpA . The measured level obtained with a sound level meter using its A-weighting network or the level as calculated per this standard. The meter shall meet the requirement

23、s of ANSI Standards S1.4. 3.7 Sound Level Rating(s). The Sound Power Level(s) of the equipment when rated in accordance with AHRI Standard 270. 3.7.1 Standard Sound Rating. The Sound Power Level(s) of the equipment when rated at Standard Rating Conditions in accordance with AHRI Standard 270. 3.7.2

24、Application Sound Rating. The Sound Power Level(s) of the equipment when rated in accordance with AHRI Standard 270 at conditions other than Standard Rating Conditions. 3.8 Unitary Air-Conditioner. One or more factory-made assemblies which normally include an evaporator or cooling coil(s), compresso

25、r(s) and condenser(s). Where such equipment is provided in more than one assembly, the separated assemblies are to be designed to be used together, and the requirements of rating outlined in this standard are based upon the use of these assemblies in operation together. 3.8.1 Functions. Either alone

26、 or in combination with a heating plant, the functions are to provide air-circulation, air cleaning, cooling with controlled temperature and dehumidification, and may optionally include the function(s) of heating and/or humidifying. Section 4. Procedure for Estimating A-Weighted Sound Pressure Level

27、(s) 4.1 Introduction. AHRI Standard 270 establishes a method of rating outdoor unitary equipment in terms of Sound Power Level(s). AHRI Standard 275 provides the methodology for estimating the A-Weighted Sound Pressure Level at a given location resulting from outdoor unitary equipment. The applicati

28、on is dependent not only upon the equipments A-Weighted Sound Power Level rating but also upon several significant factors related to the application of the equipment. These factors include equipment location, barrier shielding, sound path, and distance as described in 4.1.1 through 4.1.4 and Tables

29、 1-4. Quantitative values for each of these factors and the equipments A-Weighted Sound Power Level rating are then used to estimate the A-Weighted Sound Pressure Level at a given location. 4.1.1 Equipment Location Factor. This factor takes into consideration the effect of walls and other reflective

30、 surfaces adjacent to the equipment. Factors for typical equipment locations are given in Table 1 and described with sketches. ANSI/AHRI STANDARD 275-2010 3 Table 1. Application Factors for Estimating A-Weighted Sound Pressure Level(s) (Equipment Location Factor) Equipment Location Factor Factor Val

31、ue a. Equipment on ground, roof, or on side of building wall with no adjacent reflective surface within 3 m (d greater than 3 m) 0 dB b. Equipment on ground, roof, or on side of building wall with a single adjacent reflective surface within 3 m (d less than 3 m) On Ground or Roof Single Reflective S

32、urface 3 dB On Side of Building Single Reflective Surface c. Equipment on ground, roof, or on side of building wall within 3 m of two adjacent walls forming an inside corner (d less than 3 m to both surfaces) 6 dB On Ground or Roof Two Adjacent Reflecting Surfaces On Side of Building Two Adjacent Re

33、flecting Surfaces ANSI/AHRI STANDARD 275-2010 4 Table 1. Application Factors for Estimating A-Weighted Sound Pressure Level(s) (Equipment Location Factor) (Continued) Equipment Location Factor (continued) Factor Value d. Equipment on ground, roof, or on side of building wall and between two opposite

34、 reflecting surfaces less than 5 m apart 6 dB Distance Less Than 5 m Distance Less Than 5 m Distance Less Than 5 m ANSI/AHRI STANDARD 275-2010 5 4.1.2 Barrier Shielding Factor. This factor accounts for the sound reduction benefit of any solid structure that obstructs the line of sight (or sound) fro

35、m the equipment location to the point of evaluation. Such a barrier may be the corner of a building, the edge of a roof, or a heavy wall of masonry, etc., built for the specific purpose of shielding noise from a unit to an area of concern. See Table 2 for the normal barrier factors and Figures 1-4 f

36、or illustrative examples. Table 2. Application Factors for Estimating A-Weighted Sound Pressure Level(s) (Barrier Shielding Factor) L m 0.15 0.3 0.6 0.9 1.8 3.7 Factor Value dB 4 7 10 12 15 17 L = L1 + L2 - D 1 where: L1 + L2 = Distance from equipment to point of evaluation around barrier (Use minim

37、um L1 + L2 value.) D = Direct distance from equipment to point of evaluation with no barrier. Determine D by layout sketch. Barrier Shielding Factor (see sketches below). Sound reduction benefits can be gained when a solid structure obstructs the sound path. Examples of these structures are illustra

38、ted in Figures 1-4. D L 2 L 1 E q u ip m e n t P o int o f e v a lua t ion Figure 1. Corner of Building D L 2 L 1 E q u ip m e n t P o int o f e v a lua t ion Figure 2. Corner of Flat Roof and Wall ANSI/AHRI STANDARD 275-2010 6 D L 2 L 1 P o int o f e v a lua t ion E q u ip m e n t Figure 3. Parapet

39、 Around Flat Roof D L 2 L 1 P o int o f e v a lua t ion E q u ip m e n t B a r r ier 4.1.3 Sound Path Factor. This factor adjusts for the path of sound from the unit to the point of evaluation, which may be to the outdoors only, to a room through open windows, to a room through closed windows, or th

40、rough a wall. See Table 3. Table 3. Application Factors for Estimating A-Weighted Sound Pressure Level(s) (Sound Path Factor) Sound Path (see Figure 5) Sound Path Factor dB a. To a point of evaluation outdoors 0 b. To room through open window(s) or open door(s) 10 c. To room through closed single gl

41、ass window(s) or door 17 d. To room through closed double glass window(s) or solid wall (not illustrated) 23 Figure 5. Sound Paths According to Table 3 Path a Unit Path b Path c Path d Open Window Closed Single Pane Window Closed Double Pane Window Outdoor Patio Figure 4. Heavy Continuous Wall ANSI/

42、AHRI STANDARD 275-2010 7 4.1.4 Distance Factor. The direct distance, D, from the equipment location to the point of evaluation is a very significant application factor in determining the estimated A-Weighted Sound Pressure Level(s) resulting from the operation of outdoor equipment in any installatio

43、n. The distance factor is obtained from equation 2 and shown as an example in Table 4. 8)log(20 DDF 2 Where: Distance Factor (DF) = decrease in level based on receiver distance from source (Absolute value rounded to the nearest whole decibel), dB D= Distance from source to receiver, Meters Table 4.

44、Distance Factor D (m) 1 1.5 2 3 4 6 8 12 16 24 32 48 Factor Value (dB) 8 12 14 18 20 24 26 30 32 36 38 42 Note: The values in table 4 are rounded to the nearest whole decibel 4.2 Procedure for Estimating the A-Weighted Sound Pressure Level(s) - Single Unit Installation. The basic procedure for estim

45、ating A-Weighted Sound Pressure Level(s) at a given point of interest consists of summing the A-Weighted Sound Power Level Rating of the equipment with the Equipment Location Factor and then subtracting the Barrier Shielding Factor and the Sound Path Factor and the Distance Factor. The resultant wil

46、l be the Estimated A-Weighted Sound Pressure Level rounded to the nearest whole decibel as shown in Table 5 (see Examples 4.5.1, 4.5.2 and 4.5.3). Table 5. Calculation Procedures for Estimating A-Weighted Sound Pressure Level Line Step 1 Unit A-Weighted Sound Level Rating (AHRI Standard 270) 2 Equip

47、ment Location Factor (Table 1) 3 Add Lines 1 and 2 4 Barrier Shielding Factor (Table 2) 5 Sound Path Factor (Table 3) 6 Distance Factor (from Equation 2 or Table 4 ) 7 Add Lines 4, 5 and 6 8 Estimated A-Weighted Sound Pressure Level dBA (Subtract Line 7 from Line 3) 4.3 Procedure for Estimating the

48、A-Weighted Sound Pressure Level-Multiple Unit Installation. Estimating the A-Weighted Sound Pressure Level for multiple unit installations at any point of interest can be determined by combining the effects of each unit at the point of interest. The procedure for multi-unit installations follows that used for single un