1、 ISO 2013 Acoustics Method for measuring the influence of road surfaces on traffic noise Part 4: SPB method using backing board Acoustique Mthode de mesurage de linfluence des revtements de chausses sur le bruit mis par la circulation Partie 4: Mthode SPB avec utilisation de panneau PUBLICLY AVAILAB
2、LE SPECIFICATION ISO/PAS 11819-4 First edition 2013-03-15 Reference number ISO/PAS 11819-4:2013(E) ISO/PAS 11819-4:2013(E)ii ISO 2013 All rights reserved COPYRIGHT PROTECTED DOCUMENT ISO 2013 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized o
3、therwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright off
4、ice 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 ISO/PAS 11819-4:2013(E) ISO 2013 All rights reserved iii Contents Page Foreword iv Introduction v 1 Scope . 1 2 Normative references 1 3 Terms and defin
5、itions . 1 4 Measurement principle . 1 5 Apparatus . 2 5.1 General . 2 5.2 Backing board 2 5.3 Microphone 2 6 Test sites 4 6.1 Selection of measuring site. 4 6.2 Paired- and single-site measurements . 4 6.3 Deviations from free-field conditions . 4 6.4 Guard rails and other barriers that can reflect
6、 or screen sound 5 6.5 Surface between tested road surface and microphone 5 6.6 Special site conditions 5 7 Traffic conditions . 5 8 Measuring procedure 5 9 Normalization of data 5 9.1 Regression analysis . 5 9.2 Determination of vehicle sound level at reference speeds . 5 9.3 Useful speed range for
7、 regression line . 5 9.4 Correction of sound levels for temperature . 5 9.5 Correction for the influence of the backing board . 6 9.6 Determination of statistical pass-by index (SPBI) . 6 9.7 Measurement uncertainty . 6 10 Reference road surface 6 11 Meteorological conditions 6 12 Background noise 7
8、 13 Reported data 7 Annex A (informative) Backing board position in narrow roads or streets 8 Bibliography 9 ISO/PAS 11819-4:2013(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing Int
9、ernational 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. International organizations, governmental and non-governmental, in liaison w
10、ith 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 with the rules given in the ISO/IEC Directives, Part 2. The main task of techni
11、cal 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 approval by at least 75 % of the member bodies casting a vote. In other circumstan
12、ces, particularly when there is an urgent market requirement for such documents, a technical committee may decide to publish other types of document: an ISO Publicly Available Specification (ISO/PAS) represents an agreement between technical experts in an ISO working group and is accepted for public
13、ation if it is approved by more than 50 % of the members of the parent committee casting a vote; an ISO Technical Specification (ISO/TS) represents an agreement between the members of a technical committee and is accepted for publication if it is approved by 2/3 of the members of the committee casti
14、ng a vote. An ISO/PAS or ISO/TS is reviewed after three years in order to decide whether it will be confirmed for a further three years, revised to become an International Standard, or withdrawn. If the ISO/PAS or ISO/TS is confirmed, it is reviewed again after a further three years, at which time i
15、t must either be transformed into an International Standard or be withdrawn. 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/PAS 11819-4 was prep
16、ared by Technical Committee ISO/TC 43, Acoustics, Subcommittee SC 1, Noise. ISO/PAS 11819 consists of the following parts, under the general title Acoustics Measurement of the influence of road surfaces on traffic noise: Part 1: Statistical pass-by (SPB) method Part 2: Close-proximity (CPX) method P
17、art 3: Reference tyres Technical Specification Part 4: SPB method using backing board Publicly Available Specificationiv ISO 2013 All rights reserved ISO/PAS 11819-4:2013(E) Introduction ISO 11819-1 specifies a method for measuring the acoustic quality of roads called the statistical pass-by (SPB) m
18、ethod. Owing to severe requirements on the acoustical environment at the measurement site, the method cannot generally be used at any arbitrary location. This part of ISO 11819 complements ISO 11819-1 for applications in situations where the test conditions cannot be met such as when there may be a
19、potential influence of acoustic reflections from the rear of the measurement position. However, it must be recognized that there will be a reduction in the accuracy of the results in comparison to a true free-field measurement. ISO 2013 All rights reserved v Acoustics Method for measuring the influe
20、nce of road surfaces on traffic noise Part 4: SPB method using backing board 1 Scope This part of ISO 11819 specifies a modified version of the statistical pass-by (SPB) method given in ISO 11819-1 that uses a microphone mounted on a backing board instead of a microphone in normal, free-field condit
21、ions. It is applicable to measurements taken in an urban, built-up, environment or in the presence of safety barriers, noise barriers, embankments or road cuttings. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable
22、for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 11819-1, Acoustics Measurement of the influence of road surfaces on traffic noise Part 1: Statistical pass-by (SPB)
23、 method ISO 1996-2, Acoustics Description, measurement and assessment of environmental noise Part 2: Determination of environmental noise levels 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 11819-1 and the following apply. 3.1 backing board rectan
24、gular, hard, reflective board on which a microphone is mounted 3.2 conventional microphone free-field or pressure microphone 3.3 surface microphone flush-mounted microphone designed to measure sound pressure on a surface without requiring the drilling of a hole through it 4 Measurement principle The
25、 principle is the same as for ISO 11819-1, except that the microphone is mounted on a backing board rather than being used in normal free-field conditions. By mounting the microphone membrane very close to the backing board during measurements, noise from behind (for example, reflections from facade
26、s or noise barriers) is suppressed. The noise coming from the front is reflected by the backing board in a controlled way so that it can be taken into account by applying a correction to the measured value. In principle, the A-weighted sound pressure level increases by 6 dB due to a doubling of the
27、sound pressure caused by the backing board. PUBLICLY AVAILABLE SPECIFICATION ISO/PAS 11819-4:2013(E) ISO 2013 All rights reserved 1 ISO/PAS 11819-4:2013(E) 5 Apparatus 5.1 General The same measuring instruments as for the SPB method shall be used. Alternatively, a surface microphone may be used. 5.2
28、 Backing board 5.2.1 Dimensions The backing board shall have a rectangular shape. The width shall be 900 mm 10 mm and the height 750 mm 10 mm (see Figure 1). 5.2.2 Position The backing board shall be oriented parallel to the road and 7,50 m 0,10 m from the centre of the road lane that is the subject
29、 of the measurement. 5.2.3 Material The board shall be acoustically hard and at least 15 mm thick to avoid vibration. 1 If metal is used, the properties shall satisfy ISO 1996-2. The mass of the board shall be at least 14 kg/m 2(Reference 2 ). NOTE 1 In tests made prior to publication of this part o
30、f ISO 11819, medium-density fibre board was used and worked well. NOTE 2 More information about material properties is available in ISO 1996-2. 5.3 Microphone 5.3.1 Position The microphone shall be located in the same position relative to the road as for the SPB method according to ISO 11819-1. To a
31、chieve this, the position of the backing board is set with respect to the microphone. In order to minimize the effect of diffraction with constructive interference at the edges, position the microphone away from the centre of the board and from the boards diagonals and centrelines. Mount the microph
32、one in the upper right-hand corner of the board, 330 mm 5 mm from the right-hand edge and 230 mm 5 mm from the upper edge (see Figure 1). 4 Microphones having a diameter greater than 12,7 mm (1/2 inch) shall not be used.2 ISO 2013 All rights reserved ISO/PAS 11819-4:2013(E) Dimensions in millimetres
33、 230 5 750 10 900 10 330 5 A 1 200 10 Key A road reference level according to ISO 11819-1 Figure 1 Backing-board dimensions and microphone position as seen from sound source (independent of traffic direction) 5.3.2 Mountings The following microphone mountings are permitted: the microphone mounted as
34、 close as practicable to the board, with the casing touching the board if feasible (microphone casing parallel to the board), a surface microphone mounted flush with the surface of the board. Figure 2 shows a close-up view of the mounting. ISO 2013 All rights reserved 3 ISO/PAS 11819-4:2013(E) Left
35、free-field microphone Right surface microphone Figure 2 Examples of microphone mountings 24 A third option is to mount the microphone through a hole in the board, with the membrane flush with the board surface (see ISO 1996-2). This might be a little less practical than the other options, but gives
36、an equivalent result. 5.3.3 Effect of microphone type For the frequency range considered, it is acceptable to use either a free-field or pressure microphone. The choice of either a free-field or surface microphone can have a marginal effect on the measured levels. In general, the surface microphone
37、has the lower effect, but the differences are just a few tenths of a decibel, so no correction for microphone type is required. 5.3.4 Microphone protection The free-field microphone, if chosen, shall be protected from the influence of wind, etc., by a suitably shaped windscreen mounted around it. A
38、windscreen is not required for a surface microphone. 6 Test sites 6.1 Selection of measuring site The measuring-site selection criteria shall be those of the SPB method according to ISO 11819-1, except for criteria related to reflections from behind (see below). 6.2 Paired- and single-site measureme
39、nts Measurements shall be in accordance with ISO 11819-1. 6.3 Deviations from free-field conditions The provisions relating to acoustic reflections from objects in front of the microphone given in ISO 11819-1 apply; for reflections from behind the microphone and the backing board, there are no restr
40、ictions.4 ISO 2013 All rights reserved ISO/PAS 11819-4:2013(E) 6.4 Guard rails and other barriers that can reflect or screen sound The criteria for taking into consideration guard rails or other barriers that can reflect or screen sound shall be the same as those of the SPB method according to ISO 1
41、1819-1, except in respect of objects and reflections from behind, for which there are no restrictions. Any large object located behind the backing board (within 25 m) shall be noted in the test report, together with an estimation of its distance from the board. NOTE If there is a large object such a
42、s a building faade or bus located close behind the backing board, there could be a small increase in noise levels. Increases of up to 0,5 dB have been measured for such objects located 0,6 m behind the backing board. 1The amount of influence due to reflected sound depends on the frequency content of
43、 the vehicle noise source and the dimensions and proximity of the reflecting object. 6.5 Surface between tested road surface and microphone This surface shall be in accordance with ISO 11819-1. 6.6 Special site conditions Any special site conditions shall be in accordance with ISO 11819-1. 7 Traffic
44、 conditions The traffic conditions shall be in accordance with ISO 11819-1. 8 Measuring procedure The measuring procedure shall be in accordance with ISO 11819-1. 9 Normalization of data 9.1 Regression analysis The regression analysis shall be in accordance with ISO 11819-1. 9.2 Determination of veh
45、icle sound level at reference speeds This determination shall be in accordance with ISO 11819-1. 9.3 Useful speed range for regression line Speed shall be in accordance with ISO 11819-1. NOTE The backing board version of the SPB method has been validated only for reference speeds above 45 km/h. 1How
46、ever, there is no obvious reason why it should not work well below this speed. 9.4 Correction of sound levels for temperature This correction shall be in accordance with ISO 11819-1. ISO 2013 All rights reserved 5 ISO/PAS 11819-4:2013(E) 9.5 Correction for the influence of the backing board 9.5.1 Sp
47、eed and vehicle category In order for the reported levels of noise to be equivalent to those measured in free-field conditions, the correction values of the corresponding speed category in Table 1 shall be subtracted from the calculated vehicle sound levels for the different vehicle categories. Tabl
48、e 1 Correction values for different road speed and vehicle categories 5 Vehicle category Road speed category Name No. Low Medium High Cars 1 6,0 dB 6,0 dB 6,0 dB Dual-axle heavy vehicles 2a 6,0 dB 6,0 dB 6,0 dB Multi-axle heavy vehicles 2b 6,0 dB 6,0 dB 6,0 dBNOTE These corrected vehicle sound level
49、s are used to determine the statistical pass-by index (SPBI) (see 9.6). 9.5.2 Frequency spectra The backing board version of the SPB method should be used 1 only for road traffic noise having a fairly typical broadband spectrum and a peak at around 1 000 Hz, mainly for determining overall A-weighted sound pressure levels. Frequency spectra determined using the backing board version of the SPB method should be considered with great care. Nevertheless, it is recom
