1、 Collection of SANS standards in electronic format (PDF) 1. Copyright This standard is available to staff members of companies that have subscribed to the complete collection of SANS standards in accordance with a formal copyright agreement. This document may reside on a CENTRAL FILE SERVER or INTRA
2、NET SYSTEM only. Unless specific permission has been granted, this document MAY NOT be sent or given to staff members from other companies or organizations. Doing so would constitute a VIOLATION of SABS copyright rules. 2. Indemnity The South African Bureau of Standards accepts no liability for any
3、damage whatsoever than may result from the use of this material or the information contain therein, irrespective of the cause and quantum thereof. ISBN 978-0-626-18888-7 SANS 1470-1:2008Edition 1.2 Any reference to SABS 1470-1 is deemedto be a reference to this standard(Government Notice No. 1373 of
4、 8 November 2002)SOUTH AFRICAN NATIONAL STANDARD Sound power labelling Part 1: Compressors Published by Standards South Africa 1 dr lategan road groenkloof private bag x191 pretoria 0001 tel: 012 428 7911 fax: 012 344 1568 international code + 27 12 www.stansa.co.za Standards South Africa SANS 1470-
5、1:2008 Edition 1.2 Table of changes Change No. Date Scope Amdt 1 1999 Amended to facilitate reference to SABS ISO 3744 (which replaced SABS 0195 that is currently referenced) and to correct the criteria for the adequacy of the test environment and the background noise. Amdt 2 2008 Amended to change
6、the designation of SABS standards to SANS standards, and to update referenced standards. Acknowledgement Standards South Africa wishes to acknowledge the valuable assistance derived from publications of the following organizations: Council of the European Communities International Organization for S
7、tandardization Foreword This South African standard was approved by National Committee StanSA TC 76, Acoustics, electro-acoustics and vibration, in accordance with procedures of Standards South Africa, in compliance with annex 3 of the WTO/TBT agreement. This document was published in February 2008.
8、 This document supersedes SABS 1470-1:1999 (edition 1). A vertical line in the margin shows where the text has been technically modified by amendment No. 2.SANS 1470-1:2008 Edition 1.2 1 Contents Page Acknowledgement Foreword 1 Scope . 3 2 Definitions. 3 3 Requirements . 4 3.1 Labelling . 4 3.2 Nois
9、e emission . 5 4 Inspection and testing. 5 4.1 Inspection . 5 4.2 Test for noise emission. 5 4.3 Modifications to the test method described in SANS 3744 5 Amdt 1 Figures 1-7 . 7-10 Appendix A Applicable standards. 11 Appendix B Two-surface method to determine environmental correction K2for in-situ m
10、easurements. 12 Amdt 1 SANS 1470-1:2008 Edition 1.2 2 This page is intentionally left blank SANS 1470-1:2008 Edition 1.2 3 Sound power labelling Part 1: Compressors 1 Scope 1.1 This part of the specification covers the requirements for the labelling of compressors with a noise emission value and spe
11、cifies the test method to be used for the verification of the labelled value. NOTE a) The standards referred to in this part of the specification are listed in appendix A. b) The “two-surface method“ (see A.4.3 of SANS 3744) to determine the environmental correction is given in appendix B. Amdt 1 c)
12、 This part of the specification refers to SANS 3744 and specifies an engineering method for measuring the sound pressure levels at prescribed microphone positions on a rectangular parallelepiped surface that envelops the compressor under investigation. Amdt 1 d) For planning purposes, additional inf
13、ormation would be required, e.g. measurements of the octave or one-third octave band pressure levels. 2 Definitions 2.1 For the purposes of this part of the specification, the definitions given in SANS 3744 and the following definitions shall apply: Amdt 1 A-weighted sound power level, in decibels L
14、WAthe sound power level of a machine, determined in accordance with the test method specified in this part of the specification, with frequency weighting A (see SANS 656, SANS 658, SANS 61672-1 and SANS 61672-2) selected on the measuring instruments Amdt 2 batch a number of compressors of the same p
15、erformance and manufactured to the same technical specification by one manufacturer NOTE A batch may be either an entire production series or a portion thereof. SANS 1470-1:2008 Edition 1.2 4 batch labelling a single labelled value Lc, applied to a batch of compressors compressor a power-operated de
16、vice for compressing gases, excluding devices producing air circulation (e.g. fans) NOTE The compressor and its prime power source may be assembled as a unit or as separate individual parts. labelled value Lcan integer value, determined by the manufacturer1), representing the maximum sound power lev
17、el of a compressor near (sound) field a sound field near a sound source where instantaneous sound pressure and particle velocity are substantially out of phase 3 Requirements 3.1 Labelling Each compressor shall bear a label that contains at least the following information: a) The labelled value Lc;
18、b) the letter “B“ or “I“ to indicate batch labelling or individual labelling, respectively; c) identification of the labelled product (i.e. compressor or unit) by means of the serial number. NOTE 1) As an example, the labelling for a stationary compressor of a given power could be as follows: Labell
19、ing Interpretation(B) Lc97 23456 “(B)“ indicates that this compressor is one ofa batch that are all labelled with the samevalue: 97. The labelled value in accordance with thispart of the specification is 97. “23456“ is the serial number of the assembledunit, i.e. the labelled value includes the nois
20、eemission from the compressor as well as fromthe prime power source. 2) The labelled value may be displayed on the existing specification/information plate affixed to the compressor or unit. 3) For assessment purposes, e.g. the existence of tonal components, or for planning purposes, additional spec
21、tral information for different operating conditions would be required. 1) Guidelines for the determination of the labelled value Lcby the manufacturer are given in ISO 7574 (parts 2 to 4). Amdt 2 SANS 1470-1:2008 Edition 1.2 5 3.2 Noise emission When tested in accordance with 4.2, a compressor shall
22、 have an A-weighted sound power level LWAnot exceeding the labelled value Lc. 4 Inspection and testing 4.1 Inspection Inspect each compressor for compliance with 3.1. 4.2 Test for noise emission NOTE The standard deviation of A-weighted sound power levels determined in accordance with this part of t
23、he specification is approximately 2 dB for a source that emits noise without pronounced spectral deviations. Use the test method described in SANS 3744, modified as described in 4.3, to determine the A-weighted sound power level LWAof the compressor and check for compliance with 3.2. Amdt 1 4.3 Modi
24、fications to the test method described in SANS 3744 Amdt 1 4.3.1 Criterion for adequacy of the test environment (see 4.1 and 4.2 of SANS 3744) Amdt 1 When the test is to be carried out indoors, use one of the methods described in annex A of SANS 3744 to determine the environmental correction K2. Amd
25、t 1 If the environmental correction K2exceeds 2 dB, the test environment is not suitable for measurements in accordance with this part of the specification. Amdt 1 NOTE See note (b) to 1.1. Amdt 1 4.3.2 Criterion for background noise Amdt 1 Determine the correction for the background noise (K1) in a
26、ccordance with 8.3 of SANS 3744. Amdt 1 Averaged over the microphone positions, the level of the background noise shall be at least 6 dB, but preferably more than 15 dB, below the sound pressure level to be measured. Amdt 1 4.3.3 Instrumentation (see section 5 of SANS 3744) Amdt 1 When integrating t
27、he squared signal over a fixed time-interval, use an integrating device or system that complies with the requirements of SANS 656, SANS 658, SANS 61672-1 and SANS 61672-2. Amdt 1; amdt 2 4.3.4 Installation and operation of the compressor (see section 6 of SANS 3744) Amdt 1 a) General. Maintain the f
28、ollowing conditions: 1) Warm up the compressor by operating it in a stable condition as for continuous service at its normal rated working pressure. 2) Carry out sound pressure level measurements at rated speed and power, i.e. with the power source running at the rated full speed and with the compre
29、ssor on load delivering its rated output as specified by the manufacturer. SANS 1470-1:2008 Edition 1.2 6 b) Stationary compressors 1) Auxiliary equipment. Acoustically shield the noise generated by auxiliary equipment or components that are mounted away from the main machine, e.g. intercoolers or p
30、iping. If the labelled value Lcof the compressor applies to the compressor only and does not include the noise emission from the prime power source, noise generated by the latter should also be shielded. NOTE Some indication of the steps taken to achieve this should be specified in the test report.
31、Consider components which cannot be separated from the main compressor or unit as an integral part of the compressor or unit and measure them as such. NOTE Care should be taken to ensure that air discharge does not introduce any additional noise due to turbulence at the compressor discharge valve. 2
32、) Mounting. Structure-borne vibrations transmitted from a compressor to its mounting or to other parts of the test room can influence the sound pressure level in the test room. Minimize such effects by, for example, mounting the compressor on suitably designed resilient mountings. c) Portable (movab
33、le) compressors. During the test at full load, pipe the air discharge clear of the test area through a control valve and so feed the air discharge into an effective silencer that the discharge noise is at least 10 dB lower than the compressor noise at all measurement locations. Open all cooling air-
34、ducts fully for the duration of the test. NOTE Care should be taken to ensure that air discharge does not introduce any additional noise due to turbulence at the compressor discharge valve. 4.3.5 Measurement surface and microphone positions (see section 7.3 of SANS 3744) Amdt 1 a) Measurement surfac
35、e. Use a rectangular parallelepiped at a constant distance of 1 m from the reference surface. (See the examples given in figures 1-7.) b) Key microphone positions (see figure C.2 of SANS 3744). Use the microphone positions described in 7.3.1 of SANS 3744. Amdt 1 c) Additional microphone positions (s
36、ee 7.3.2 of SANS 3744). If measurements at additional microphone positions are required, choose these positions in accordance with figure C.1 of SANS 3744. Amdt 1 d) Reduction of number of microphone positions. The nine key points may be reduced to five (numbers 1, 2, 3, 4 and 9 in figure C.2 of SAN
37、S 3744) if it has been proven that the surface sound pressure level determined in this way on a similar compressor does not deviate by more than 1,0 dB from the value determined using nine key points. NOTE The overhead microphone position may be omitted for safety purposes. Amdt 1 SANS 1470-1:2008 E
38、dition 1.2 7 4.3.6 Measurement of the A-weighted sound pressure level (see subsection 7.5 of SANS 3744) Amdt 1 Obtain the following data: a) the A-weighted sound pressure level during operation of the compressor under test; and b) the A-weighted sound pressure level of the background noise with the
39、compressor inoperative. 4.3.7 Calculation of the A-weighted sound power level Calculate the A-weighted sound power level of the compressor in accordance with section 8 of SANS 3744. Amdt 1 Figure 1 Reference and measurement surfaces applied to a portable compressor SANS 1470-1:2008 Edition 1.2 8 Fig
40、ure 2 Stationary compressor with reference surface Figure 3 Small stationary compressor with reference surface SANS 1470-1:2008 Edition 1.2 9 NOTE For large units, the suction inlet is often in a different location from the compressor. Figure 4 Rotary vane compressor with reference surface Figure 5
41、Rotary positive displacement compressor with reference surface SANS 1470-1:2008 Edition 1.2 10 Figure 6 Centrifugal compressor with reference surface Figure 7 Integral gear centrifugal compressor with reference surface SANS 1470-1:2008 Edition 1.2 11 Appendix A Applicable standards Reference is made
42、 to the latest issues of the following standards: ISO 7574-1, Acoustics Statistical methods for determining and verifying stated noise emission values of machinery and equipment Part 1: General considerations and definitions. ISO 7574-2, Acoustics Statistical methods for determining and verifying st
43、ated noise emission values of machinery and equipment Part 2: Methods for stated values for individual machines. ISO 7574-3, Acoustics Statistical methods for determining and verifying stated noise emission values of machinery and equipment Part 3: Simple (transition) method for stated values for ba
44、tches of machines. ISO 7574-4, Acoustics Statistical methods for determining and verifying stated noise emission values of machinery and equipment Part 4: Methods for stated values for batches of machines. SANS 656, Sound level meters. Amdt 2 SANS 658, Integrating-averaging sound level meters. Amdt
45、2 SANS 3744/ISO 3744, Acoustics Determination of sound power levels of noise sources using sound pressure Engineering method in an essentially free field over a reflecting plane. Amdt 1 SANS 61672-1/IEC 61672-1, Electroacoustics Sound level meters Part 1: Specifications. Amdt 2 SANS 61672-2/IEC 6167
46、2-2, Electroacoustics Sound level meters Part 2: Pattern evaluation tests. Amdt 2 SANS 1470-1:2008 Edition 1.2 12 Appendix B Two-surface method to determine the environmental correction K2for in-situ measurements Amdt1 (This appendix forms part of the requirements of the specification) B.1 General N
47、ormally, the noise level of a compressor is determined outdoors under free-field conditions or in special test rooms for which the environmental correction has been determined. Determination of the sound pressure level of a stationary compressor, particularly a large machine, can, in some cases, onl
48、y be carried out in situ, with the result that the acoustic environment is far from ideal. The environmental correction K2which needs to be applied in such cases, may be determined in accordance with the absolute comparison test, or by using one of the methods based on room absorption (see annex A o
49、f SANS 3744). The method given in this appendix is based on the “two-surface method“ given in A.4.3 of SANS 3744. Amdt 1 B.2 Measurement surfaces and microphone locations For the qualification of the environment, use two measurement surfaces as follows: a) The first is the same surface as is used when the sound power level of the compressor under test is being determined and this area is designated S1; b) the second is geometrically similar to the first one, but located further away from the compressor under test. The area of this measurem
