1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 13472-2:2010Acoustics Measurement ofsound absorption properties ofroad surfaces in situPart 2: Spot method for reflective surfacesBS ISO 13472-2:2010 BRITISH STANDARDNatio
2、nal forewordThis British Standard is the UK implementation of ISO 13472-2:2010.The UK participation in its preparation was entrusted to TechnicalCommittee EH/1/2, Transport noise.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does no
3、t purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. BSI 2010ISBN 978 0 580 58671 2ICS 17.140.30; 93.080.20Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the author
4、ity of theStandards Policy and Strategy Committee on 30 November 2010.Amendments issued since publicationDate Text affectedBS ISO 13472-2:2010Reference numberISO 13472-2:2010(E)ISO 2010INTERNATIONAL STANDARD ISO13472-2First edition2010-05-15Acoustics Measurement of sound absorption properties of roa
5、d surfaces in situ Part 2: Spot method for reflective surfaces Acoustique Mesurage in situ des proprits dabsorption acoustique des revtements de chausses Partie 2: Mthode ponctuelle pour les surfaces rflchissantes BS ISO 13472-2:2010ISO 13472-2:2010(E) PDF disclaimer This PDF file may contain embedd
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8、re optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below. COPYRIGHT PROTECTED DOCUMENT ISO 2010 All rights rese
9、rved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the reques
10、ter. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2010 All rights reservedBS ISO 13472-2:2010ISO 13472-2:2010(E) ISO 2010 All rights reserved iiiContents Page Foreword iv In
11、troduction.v 1 Scope1 2 Normative references1 3 Terms and definitions .2 4 Principle2 5 Test equipment 4 5.1 Components of the test system.4 5.2 Sound source.4 5.3 Test signal4 5.4 Impedance tube .4 5.4.1 Tube diameter 4 5.4.2 Tube length and microphone positions5 5.5 Microphones 6 5.6 In-situ test
12、fixture between impedance tube and test surface6 5.7 Signal-processing system6 5.8 Thermometer and pressure measurement .6 6 Measurement and analysis procedure 6 6.1 Stabilizing the system.6 6.2 Calibration of the system7 6.3 Reference measurement.7 6.4 Background noise measurement.7 6.5 Measurement
13、 of a road surface .7 6.6 Data analysis8 7 Positioning of the equipment.8 7.1 Location of the measurement positions .8 7.1.1 Test surfaces such as those meeting ISO 10844 requirements .8 7.1.2 Regular roads 8 7.2 Condition of the road surface 8 7.3 Temperature.8 8 Measurement and analysis procedure
14、8 9 Measurement uncertainty.9 10 Test report11 Annex A (normative) Correction on base of reference measurement 12 Annex B (informative) Measurement uncertainty 13 B.1 General .13 B.2 Expression for the calculation of the absorption coefficient .13 B.3 Sources of uncertainty14 B.4 Expanded uncertaint
15、y of measurement15 Annex C (informative) Sketch of in-situ test fixture 16 Annex D (informative) Example of a test report.18 Bibliography20 BS ISO 13472-2:2010ISO 13472-2:2010(E) iv ISO 2010 All rights reservedForeword ISO (the International Organization for Standardization) is a worldwide federatio
16、n of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee.
17、 International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance wi
18、th the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires appro
19、val by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 13472-2 was prepared by Technical Commi
20、ttee ISO/TC 43, Acoustics, Subcommittee SC 1, Noise. ISO 13472 consists of the following parts, under the general title Acoustics Measurement of sound absorption properties of road surfaces in situ: Part 1: Extended surface method Part 2: Spot method for reflective surfaces BS ISO 13472-2:2010ISO 13
21、472-2:2010(E) ISO 2010 All rights reserved vIntroduction This part of ISO 13472 specifies a test method for measuring in situ the sound absorption coefficient of road surfaces as a function of frequency under normal incidence. This method enables evaluation of the sound absorption characteristics of
22、 a road surface without damaging the surface. It is intended to be used to qualify the absorption characteristics of road surfaces used for vehicle and tyre testing. It may also be used during road construction, road maintenance, and other traffic noise studies. However, the field of application is
23、limited to low absorption surfaces. The method specified in this part of ISO 13472 is based on propagation of the test signal from the source to the road surface and back to the receiver through an impedance tube. The tube covers an area of approximately 0,008 m2and a frequency range, in one-third-o
24、ctave bands, from 250 Hz to 1 600 Hz. It uses the test procedure and signal processing specified in ISO 10534-2, but because of the defined frequency range of application, the dimensions of the system are not adjustable, but fixed. This method is primarily intended for smooth low absorption surfaces
25、, such as those in accordance with ISO 10844. The method is not reliable if the measured sound absorption coefficient exceeds 0,15. Surfaces with values above 0,10 are not considered to be reflective. This method is complementary to the extended surface method (ISO 13472-15) that covers an area of a
26、pproximately 3 m2and a frequency range, in one-third-octave bands, from 250 Hz to 4 000 Hz. Both methods should give similar results in the frequency range from 315 Hz to 1 600 Hz, but their fields of application and therefore their accuracy differ strongly. The method described in ISO 13472-15has l
27、imited accuracy at small sound absorption values and is therefore unsuitable for checking compliance of surfaces with the requirements of such documents as ISO 10844, while the method specified here fails at higher sound absorption values. Within their ranges, the methods are also applicable to acou
28、stic materials other than road surfaces. The measurement results of this method are comparable to the results of the impedance tube method, performed on bore cores taken from the surface in accordance with documents such as ISO 10534-14, ISO 10534-2 and ASTM E10507. The measurement results obtained
29、with this method are in general not comparable to the results of the reverberation room method (ISO 3541), because the method described in this part of ISO 13472 uses a plane progressive wave at perpendicular incidence, while the reverberation room method uses a diffuse sound field. BS ISO 13472-2:2
30、010BS ISO 13472-2:2010INTERNATIONAL STANDARD ISO 13472-2:2010(E) ISO 2010 All rights reserved 1Acoustics Measurement of sound absorption properties of road surfaces in situ Part 2: Spot method for reflective surfaces 1 Scope This part of ISO 13472 specifies a test method for measuring in situ the so
31、und absorption coefficient of road surfaces for the one-third-octave-band frequencies ranging from 250 Hz to 1 600 Hz under normal incidence conditions. For special purposes, the frequency range can be changed by modifying the dimensions of the system. The test method is intended for: a) determinati
32、on of the sound absorption coefficient of semi-dense to dense road surfaces (and, if of interest, also the complex acoustical impedance); b) determination of the sound absorption properties of test tracks in accordance with standards such as ISO 10844 and test surfaces defined in national and intern
33、ational type approval regulations for road vehicles and vehicle tyres; c) verification of the compliance of the sound absorption coefficient of a road surface with design specifications or other requirements. 2 Normative references The following referenced documents are indispensable for the applica
34、tion of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 10534-2:1998, Acoustics Determination of sound absorption coefficient and impedance in impedance tubes Part 2: Tr
35、ansfer-function method ISO 10844, Acoustics Specification of test tracks for measuring noise emitted by road vehicles and their tyres ISO/IEC Guide 98-3:2008, Uncertainty of measurement Part 3: Guide to the expression of uncertainty in measurement (GUM:1995) IEC 61260, Electroacoustics Octave-band a
36、nd fractional-octave-band filters BS ISO 13472-2:2010ISO 13472-2:2010(E) 2 ISO 2010 All rights reserved3 Terms and definitions For the purposes of this document, the following definitions apply. 3.1 frequency range frequency interval in which measurements are valid specified in one-third-octave band
37、s in accordance with IEC 61260 NOTE The frequency range is specified in one-third-octave bands. This means that its lower limit is the lower limit of the lowest one-third-octave band specified and its upper limit is the upper limit of the highest one-third-octave band specified. The frequency range
38、specified in one-third-octave bands of 250 Hz to 1 600 Hz centre frequency implies a frequency range specified in narrow bands of 220 Hz to 1 800 Hz. 3.2 sound absorption coefficient at normal incidence ratio of sound power entering the surface of the test object (without return) to the incident sou
39、nd power for a plane wave at normal incidence ISO 10534-2:1998, 2.1 3.3 sound pressure reflection factor at normal incidence r complex ratio of the pressure of the reflected wave to the pressure of the incident wave at the surface of the test object for a plane wave at normal incidence 3.4 plane of
40、reference for the road surface hypothetical plane defined by the underside of the sealing device at which the sound pressure reflection factor is calculated 3.5 signal-to-noise ratio level difference, in decibels, between the level of the useful signal and the level of the background noise 3.6 norma
41、l surface impedance Z ratio of the complex sound pressure to the normal component of the complex sound particle velocity at an individual frequency in the reference plane NOTE 1 Adapted from ISO 10534-2:1998, 2.4. NOTE 2 Although not used in specifications of road surfaces, calculating propagation o
42、ver such a surface requires a complex acoustic impedance. 4 Principle The two microphone impedance tube method (see ISO 10534-2 or ASTM E10507) is adapted to a portable apparatus that enables the normal incidence sound absorption coefficient of plane surfaces to be rapidly measured over a broad freq
43、uency range without distortion of the surface. The procedure enables a single skilled operator to perform such measurements. There is no need for a calibration for microphones as required in typical acoustic measurements, but it does require a specific verification of the two microphone apparatus fo
44、r amplitude and phase relationship between microphones at the time of the measurement and a determination of the internal energy loss of the system based on measurements on a totally reflecting plane. BS ISO 13472-2:2010ISO 13472-2:2010(E) ISO 2010 All rights reserved 3The apparatus is a standard im
45、pedance tube utilizing the two microphone arrangement. A sound signal from a loudspeaker located at one end propagates through the tube. The open end of the tube is placed on the surface to be measured. The complex acoustic transfer function of the two microphone signals is determined and used to co
46、mpute the normal incidence sound absorption coefficient and related quantities. The absorption coefficient covers the one-third-octave-band frequency range from 250 Hz to 1 600 Hz. Figure 1 illustrates the system set-up. Key 1 loudspeaker 2 vibration isolation 3 microphones 4 in-situ test fixture 5
47、sound source and amplifier 6 frequency analyser 7 surface under test Figure 1 Configuration of the measuring device and related equipment BS ISO 13472-2:2010ISO 13472-2:2010(E) 4 ISO 2010 All rights reservedThe signal processing is described in ISO 10534-2 and ASTM E10507and consists basically of th
48、e measurement of the complex transfer function between the two microphones in the presence of the sample under test. This is then processed to obtain the complex pressure reflection factor from which the acoustic absorption can be calculated. The procedure described in ISO 10534-2 and ASTM E10507inc
49、ludes the calibration of amplitude and phase properties of the two microphones. In this method, the test sample holder specified in ISO 10534-2 is replaced by an in-situ test fixture that enables an airtight connection between the inside of the test tube and the surface of the road under test. The test tube and the fixture can be either integrated into a single piece or connected by some kind of fixing device and an airtight seal such as a rubber O-ring. On the underside of the in-situ test f
