INTERNATIONAL STANDARD ISO 1 81 9-2 First edition 2017-03 Acoustics — Measurement of the influence o f road surfaces on tra ffic noise — Part 2: The close-proximity method Acoustique — Méthode de mesurage de l’influence des revêtements de chaussées sur le bruit émis par la circulation — Partie 2: Méthode de proximité immédiate Reference number ISO 11819-2:2017(E) © ISO 2017 ISO 11819-2:2017(E) COPYRIGHT PROTECTED DOCUMENT © ISO 2017, Published in Switzerland All rights reserved Unless otherwise specified, no part o f this publication may be reproduced or utilized otherwise 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 ISO’s member body in the country o f the requester ISO copyright o ffice Ch de Blandonnet • CP 401 CH-1214 Vernier, Geneva, Switzerland Tel +41 22 749 01 11 Fax +41 22 749 09 47 copyright@iso.org www.iso.org ii © ISO 2017 – All rights reserved ISO 1 81 9-2 : 01 7(E) Contents Page v Introduction vi Scope Normative re ferences Terms and definitions 3.1 Road and pavement related definitions 3.2 Measurement methods and equipment 3.3 Acoustic quantities and symbols 3.4 Symbols used for correction terms 4 Symbols and abbreviated terms Measurement principle 6 Measuring instruments 6.1 Sound level instrumentation 6.2 Frequency analysis instrumentation 6.3 Sound calibration instrumentation 6.4 Vehicle speed measuring instrumentation 6.5 Position monitoring instrumentation 6.6 Temperature measuring instrumentation 6.7 Tyre load measuring equipment 6.8 Inflation pressure measuring equipment 6.9 Verification o f measuring system and measuring instrumentation 7 Test sites 8 Meteorological conditions 8.1 Wind 8.2 Temperature and other weather-related issues Test vehicle 9.1 General design 9.2 Microphone positions and mounting 9.3 Performance requirements and formity o f the test vehicle 11 9.4 Re ference tyres 11 9.5 Tyre rubber hardness 11 9.6 Tyre mounting 11 9.7 Tyre run-in 12 10 Measurement procedure 10.1 Preparations for measurements 12 10.2 Measurement of sound 12 10.3 Procedure for study o f typical road section 12 10.4 Minimum number o f runs for very short road sections 13 10.5 Lateral position on the road 13 10.6 Longitudinal position on the road 13 10.7 Consideration of disturbing noise 13 10.8 Test vehicle speed 13 10.8.1 Reference speeds 13 10.8.2 Test speed and acceptable deviations 13 10.9 Tyre loads 14 10.10 Tyre inflation 14 10.11 Temperature measurement 14 10.11.1 General 14 10.11.2 Air temperature 15 10.11.3 Road surface temperature (optional) 15 Foreword © ISO 2017 – All rights reserved iii ISO 1 81 9-2 : 01 7(E) 10.12 Overview and summary 15 11 Analysis procedure 11.1 15 Definition o f steps in the calculation process 15 11.2 Results expressed as overall levels 16 11.2.1 General 16 11.2.2 Case A 17 11.2.3 Case B 17 11.2.4 Expression of CPX levels 17 11.3 Results expressed as one-third-octave-band levels 18 11.3.1 General 18 11.3.2 Case A 18 11.3.3 Case B 18 11.4 Correction for analysis o f spectral levels 18 11.5 Acoustic variability 18 19 13 Repeatability and reproducibility: System comparison according to ISO 72 -2 14 Test report Annex A (normative) Certification o f the test vehicle Annex B (normative) Averaging within each road segment Annex C (informative) Detailed explanation o f the calculation procedure Annex D (informative) Applicability o f ISO 1 81 methods Annex E (informative) Guidelines for design and use o f the test vehicle 39 Annex F (informative) Guidelines for measurements 43 Annex G (informative) Application o f the CPX method for surveying large road networks 45 Annex H (informative) Application o f the CPX method for other obj ectives 48 Annex I (informative) Summary o f measurement parameters 49 Annex J (informative) Validity and stability o f the method Annex K (informative) Measurement uncertainty 53 Annex L (informative) Re ference road surface 56 Annex M (informative) Calculation o f close-proximity sound indices 58 Annex N (informative) Summary o f measuring and data-processing procedures 59 Annex O (informative) Example o f test report 61 Bibliography 64 12 iv Measurement uncertainty assessment according to ISO/IEC Guide 98-3 © ISO 2017 – All rights reserved ISO 11819-2:2017(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies) The work o f 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 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 o f electrotechnical standardization The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part In particular the different approval criteria needed for the di fferent types o f ISO documents should be noted This document was dra fted in accordance with the editorial rules of the ISO/IEC Directives, Part (see www.iso org/directives) Attention is drawn to the possibility that some o f the elements o f this document may be the subject o f patent rights ISO shall not be held responsible for identi fying any or all such patent rights Details o f any patent rights identified during the development o f the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso org/patents) Any trade name used in this document is in formation given for the convenience o f users and does not constitute an endorsement For an explanation on the voluntary nature o f standards, the meaning o f ISO specific terms and expressions related to formity assessment, as well as in formation about ISO’s adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following URL: www.iso org/iso/foreword html This document was prepared by Technical Committee ISO/TC 43, Acoustics, Subcommittee SC 1, Noise A list of all parts in the ISO 11819 series can be found on the ISO website © ISO 2017 – All rights reserved v ISO 1 81 9-2 : 01 7(E) Introduction The emission and propagation o f road tra ffic noise greatly depends on road sur face characteristics, notably on texture, flow resistivity and acoustic absorption All these characteristics influence the generation of tyre/road noise and, in addition, the acoustic absorption can influence the propagation o f sound, particularly when the propagation takes place close to the sur face Power unit noise, which is usually generated at a greater height above the road sur face than tyre/road noise, may also be a ffected during propagation by the porosity characteristics o f the road sur face These effects lead to di fferences in sound pressure levels, associated with a given tra ffic flow and composition, from di fferent road sur faces o f up to 15 dB, which can have a substantial impact on the environmental quality alongside a road It is there fore important to be able to measure the influence o f sur face characteristics on tyre/road noise by a standardized method Within the constraints o f this method, this document o ffers an objective rating o f the road characteristics to satis fy a need expressed by road planners, road administrators, contractors, manufacturers of so-called “low-noise surfaces” and other parties concerned with the control o f road tra ffic noise A method satis fying the needs expressed in the foregoing, but having serious practical constraints, appears in ISO 11819-1 That method, called the statistical pass-by (SPB) method, is intended for use essentially for two main purposes It can be used: first, to classi fy sur faces in typical and good condition as a type according to their influence on tra ffic noise (sur face classification); and second, to evaluate the influence on tra ffic noise o f di fferent sur faces at particular sites irrespective o f condition and age However, due to severe requirements on the acoustical environment at the measurement site, In addition, the SPB method has a number of other practical limitations, which are outlined in Annex D the method cannot generally be used for approval o f new or rebuilt sur faces at any arbitrary location The method specified in this document, together with ISO/TS 11819-3, complements the SPB method in applications where the latter has limitations vi © ISO 2017 – All rights reserved INTERNATIONAL STANDARD ISO 1 81 9-2 : 01 7(E) Acoustics — Measurement o f the influence o f road surfaces on tra ffic noise — Part 2: The close-proximity method Scope T h i s c u ment s p e ci fie s a me tho d o f eva luati ng d i fferent ro ad s u r face s with re s p e c t to thei r i n fluence on tra ffic noi s e, under cond ition s when tyre/ro ad noi s e dom i nate s T he i nterpre tation o f the re s u lts app l ie s to fre e -flowi ng tra ffic travel l i ng on e s s enti a l ly level ro ad s at s tant s p e e d s o f km/ h and up ward s , i n wh ich c as e s tyre/ro ad noi s e i s a s s u me d to dom i nate (a lthough i n s ome cou ntrie s it i s p o s s ible th at tyre/ro ad noi s e e s no t dom i nate at km/ h when the prop or tion o f he av y veh icle s i s h igh) For o ther d rivi ng cond ition s where tra ffic i s no t fre e -flowi ng , s uch as at j u nc tion s or u nder he av y acceleration, and where the tra ffic i s conge s te d , the i n fluence o f the ro ad s ur face on noi s e em i s s ion i s more complex This is also the case for roads with high longitudinal gradients and a high proportion of he av y veh icle s A standard method for comparing noise characteristics of road surfaces gives road and environment authorities a tool for establishing common practices or limits as to the use of surfacings meeting certain noise criteria However, it is not within the scope of this document to suggest such criteria I S O 11 819 -1 defi ne s a no ther me tho d: the s tati s tic a l p as s-b y (S PB) me tho d T he clo s e -proxi m ity (C PX ) me tho d s p e ci fie d i n the pre s ent c u ment h as the s a me mai n obj e c tive s as the S PB me tho d, but i s i ntende d to b e u s e d s p e c i fica l ly i n appl ic ation s that a re complementa r y to it, s uch a s: — noi s e charac teri z ation o f ro ad s u r face s at a l mo s t any arbitrar y s ite, with the mai n pu rp o s e o f che cki ng compl ia nce with a s u r face s p e c i fic ation (an e xample for form ity o f pro duc tion is suggested in Reference [1 — checking the acoustic effect of maintenance and condition, e.g wear of and damage to surfaces, as ] ); wel l as clo ggi ng a nd the e ffe c t o f cle an i ng o f p orou s s u r face s; — che cki ng the longitud i na l a nd latera l homo geneity o f a ro ad s e c tion; — the development o f quie ter ro ad s u r face s a nd re s e arch on tyre/ro ad i nterac tion NOTE This document does not describe the conditions of application for formal purposes of the measurement f f Annex D with the C P X me tho d S uch cond itio n s m ay b e de fi ne d i n o ther s ta nda rd s o r le ga l te x ts H owe ver, s ugge s tio n s the ap p l ic ab i l ity o or I S O 1 819 -1 a nd th i s c u ment a re p rovide d i n Measurements with the CPX method are faster and more practical than with the SPB method, but are more l i m ite d i n the s en s e th at it i s relevant on ly i n c as e s where tyre/ro ad noi s e dom i nate s and p ower u nit noi s e c an b e negle c te d Fu r thermore, it c a nno t ta ke he av y veh icle tyre/ro ad noi s e i nto account a s fu l ly as the S PB me tho d c an, s i nce it u s e s a l ight truck tyre a s a prox y not take power unit noise into account for he av y veh icle tyre s and e s T he C PX me tho d s p e ci fie d i n th i s c u ment i s i ntende d to me as u re the prop er tie s o f ro ad s u r face s , no t the prop er tie s o f tyre s I f the me tho d i s u s e d for re s e a rch pu rp o s e s , to provide an i nd ic ation o f d i fference s b e twe en tyre s , the lo ad s and i n flation s wou ld norma l ly b e adj u s te d to o ther va lue s than s p e ci fie d i n th i s c u ment © ISO 2017 – All rights reserved ISO 1 81 9-2 : 01 7(E) T he Normative re ferences fol lowi ng c u ments are re ferre d to i n the te xt i n s uch a way that s ome or a l l o f thei r content s titute s re qu i rements o f th i s c u ment For date d re ference s , on ly the e d ition c ite d appl ie s For undate d re ference s , the l ate s t e d ition o f the re ference d c u ment (i nclud i ng a ny amend ments) appl ie s ISO 5725-2, Accuracy (trueness and precision) ofmeasurement methods and results — Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method ISO 11819-1, Acoustics — Measurement o f the influence o f road surfaces on traffic noise — Part 1: Statistical Pass-By method ISO/TS 11819-3, Acoustics — Measurement of the influence of road surfaces on traffic noise — Part 3: Reference tyres ISO/TS 13471-1, Acoustics — Temperature influence on tyre/road noise measurement — Part 1: Correction for temperature when testing with the CPX method IEC 60942, Electroacoustics — Sound calibrators IEC 61260-1, Electroacoustics — Octave-band and fractional-octave-band filters — Part 1: Specifications IEC 61672-1, Electroacoustics — Sound level meters — Part 1: Specifications ISO/IEC Guide 98-3, Uncertainty of measurement — Part 3: Guide to the expression of uncertainty in measurement (GUM: 1 995) Terms and definitions ISO 11819-1 f ISO and IEC maintain terminological databases for use in standardization at the following addresses: — IEC Electropedia: available at http://www.electropedia org/ — ISO Online browsing platform: available at http://www.iso org/obp For the purp os es o f this cument, the terms and definitions given in and the ol lowing apply Road and pavement related definitions 3.1.1 road section to ta l s tre tch o f the ro ad lane s ubj e c t to te s ti ng road segment part of a road section, being 20 m long and intended for normalization of sound pressure levels from the actual speed on that segment to a certain reference speed Measurement methods and equipment statis tical pass-by method SPB method me a s urement pro ce du re de s igne d to eva luate veh icle and tra ffic noi s e generate d on d i fferent s e c tion s o f ro ad s u r face u nder s p e ci fic tra ffic cond ition s N o te to entr y: T he me a s u rements a re ta ken from a gre at nu mb er o f veh icle s o p erati ng no r m a l l y on the ro ad Re s u lts ob ta i ne d u s i n g th i s pro ce du re a re no rm a l i z e d to s ta nd a rd s p e e d s acco rd i n g to the c ate gor y o r typ e o f ro ad b ei n g s idere d T he me tho d i s s p e c i fie d i n I S O 1 19 -1 © ISO 2017 – All rights reserved ISO 1 81 9-2 : 01 7(E) 3.2.2 re ference tyres test tyres specified for the purpose o f representing certain features in tyre/road sound emission, designed and constructed for use in this method with specified and reproducible standard properties Note to entry: The re ference tyres are specified in ISO/TS 11819-3 3 Acoustic quantities and symbols 3.3.1 close-proximity level CPX level CPX time-averaged A-weighted sound pressure level (SPL) o f the tyre/road noise as determined by the CPX L method, either broadband or spectral bands, as required Note to entry: The CPX level is expressed in decibels In order to provide more in formation, additional su ffixes are used; see Table 3.3.2 CPX level for passenger cars and other light vehicles LCPX:P A-weighted sound pressure level characterizing the road surface under test, which is based on the tyre/road sound pressure levels o f one or more tyres representative o f passenger car tyres Note to entry: The 3.3.3 CPX level LCPX:P is expressed in decibels Passenger car tyres are denoted P1, P2 … for heavy vehicles LCPX:H A-weighted sound pressure level characterizing the road surface under test, which is based on the tyre/road sound pressure levels o f one or more tyres representative o f heavy vehicle tyres Note to entry: The LCPX:H is expressed in decibels Heavy vehicle tyres are denoted H1, H2 … 3.3.4 CPX index LCPX:I index composed of the weighted average of the CPX level for passenger cars and other light vehicles ( LCPX:P ) and CPX level for heavy vehicles ( LCPX:H ) Note to entry: The LCPX:I is expressed in decibels The method is intended to describe performance of road sur faces for a certain tra ffic composition in a similar way to the SPB method in ISO 11819-1, although the numerical values for a given speed are higher More information on the calculation of CPX indices is given in Annex M 3.3.5 acous tic variability due to road sur face inhomogeneities t standard deviation of the A-weighted sound pressure levels over all segments, when using reference tyre t s Note to entry: The acoustic variability is expressed in decibels This variability is normally dominated by road surface variations, although random uncertainties could add a little Measurement speed and wheel tracks normally not influence this value significantly This measure is, there fore, considered to be an indication o f road sur face homogeneity as far as noise properties are concerned © ISO 2017 – All rights reserved ISO 1 81 9-2 : 01 7(E) Symbols used for correction terms 3.4.1 measured speed ν actual speed during a measurement Note to entry: The measured speed is expressed in kilometres per hour re ference speed vref preferred speed for measurement Note to entry: The re ference speed is expressed in kilometres per hour Most commonly used re ference speeds are 50 km/h, 80 km/h and 110 km/h, but alternative speeds may be used i f required for technical, sa fety or legislative reasons 3.4.3 speed coe fficient B coe fficient determining the speed dependence o f the sound pressure levels, normally used for correction of the sound pressure level to a certain reference speed Note to entry: The correction for deviations from the re ference speed is given by the expression B⋅lg(v/vref), expressed in decibels, where B is dimensionless Values of B for specific pavements are given in 11.1 d) 3.4.4 temperature coe fficient γt coe fficient used for correcting CPX level for the e ffect o f temperature for tyre t Note to entry: The temperature coe fficient is expressed in decibels per degree Celcius 3.4.5 rubber hardness coe fficient βt coe fficient used for correcting CPX level for the e ffect o f tread rubber hardness o f tyre t Note to entry: The rubber hardness coe fficient is expressed in decibels per Shore A Re fer to application 3.4.6 device- dependent correction Cd, f for sound 11.1 f) for reflections correction for individual measuring devices in one-third-octave bands from 315 Hz to 000 Hz with the centre frequency f, to account for deviations from acoustic hemi- free-field conditions Note to entry: The device correction for sound reflections is expressed in decibels In formation on the determination of Cd, f is given in A.2 Symbols and abbreviated terms Table lists the symbols used in this document All acoustic variables are A-weighted © ISO 2017 – All rights reserved ISO 1 81 9-2 : 01 7(E) J.5 Stability o f measured results Despite the various validity problems discussed in J.1 to which makes it suitable in many applications, see Annex D J.4, the method also has major advantages Stability with time o f this method is good in some respects and poor in others The re ference tyres are assumed to have relatively stable noise emission characteristics, provided they are properly stored and exchanged at suitable intervals 6) This ensures that results of measurements made many years apart and perhaps in different parts of the world are comparable Yet the experience is that without the control required in this document, variability related to tyres, in combination with meteorology, is a huge problem Without observing these tyre-related requirements and recommendations, as well as weather-related influences, the CPX method is almost useless Another aspect o f time influence is that the fleet o f vehicles and the fleet o f tyres used on them changes with time, and such an e ffect cannot be picked up with this method This may be both an advantage and a disadvantage If representativity o f actual traffic noise is of primary concern, it is necessary to consider the e ffect o f changes with time in tyre design for tyres used in actual tra ffic; in particular, to study i f such e ffects significantly a ffect the sur face influence 6) 52 Re fer to ISO/TS 11819-3; see the Introduction © ISO 2017 – All rights reserved ISO 1 81 9-2 : 01 7(E) Annex K (informative) Measurement uncertainty K.1 General The result o f the application o f the procedure described in this document is subject to disturbance by several factors and processes The cause and nature o f these disturbances are either known, but randomly distributed in an uncontrollable way, or are o f a systematic nature, but a ffect the result in an unpredictable way In accordance with ISO/IEC Guide 98-3, the effects are evaluated on the base of their contribution to the combined standard uncertainty and then a coverage probability is defined, resulting in a coverage factor k by which the combined standard uncertainty is multiplied, yielding the expanded uncertainty K.2 Expression for the calculation o f the CPX level The general expression for the determination o f the CPX level is given by Formula (13) K.3 Sources o f uncertainty δ1 The measurement procedure assumes driving at the re ference speed with test tyres located in the wheel track The sound pressure levels ideally are recorded on the basis o f its equivalent level during the total length o f the segment In reality, deviations from these conditions occur Speed deviations can partly be corrected for; other sources o f deviations cannot be corrected for Segments subjected to disturbing noise are removed from the analysis K.3 δ2 The equipment used for measuring the sound pressure level, the air temperature and the vehicle speed exhibit limited accuracy Although calibration o f the sound measuring chain limits the K.3 error, it does not cancel out a residual error δ3 The environmental conditions are assumed to be a temperature of 20 °C and a road surface in dry and debris free condition In reality, deviations from this situation occur A correction procedure for deviating temperature is given, but the coe fficient may be di fferent for other road surfaces as the K.3 reference δ4 The effect of disturbing noise is limited with the requirement of a signal-to-noise ratio of dB, but still affects the overall result, especially since detection o f disturbed segments is based on an increment o f dB Non-enclosed systems are vulnerable to this type o f disturbance Application o f enclosure has a beneficial e ffect on this source, but cannot totally exclude it K.3 K.3 δ5 The test vehicle or towing vehicle may give unwanted contributions due to reflections from the vehicle structure and enclosure and to rolling noise and propulsion noise from the (towing) vehicle Although the device specific correction covers most o f the systematic e ffect, a residual e ffect remains δ6 The selected re ference tyre may change its properties with time and wear Some o f these properties depend on temperature and sti ffness o f the rubber, but these are compensated for by the K.3 correction procedures There is also a certain spread in noise properties between different samples of the same tyre type © ISO 2017 – All rights reserved 53 ISO 1 81 9-2 : 01 7(E) NOTE The input quantities in Table K.1 to allow for uncertainties are those thought to be applicable according to the state of knowledge at the time of publication of this document, but further research could reveal that there are others In K.4 , an exa mp le i s given for a typic a l me a s u rement o f a ro ad s e c tion and with a s ys tem me e ti ng the re qu i rements s tate d i n the ma i n b o dy o f th i s c u ment K.4 Estimation o f uncertainties I n the pro ce du re i n th i s c ument, the s ou rce s o f uncer ta i nty a nd the re s u lti ng s pre ad i n the end re s u lt listed in Table K.1 f test vehicle (trailer or self-powered, according to Clause 9) c an b e d i s ti ngu i s he d For i n ormation ab out the i nter pre tation o f the prob abi l ity d i s tribution s , re fer to I S O/I E C Guide -3 T he term s “enclo s u re” a nd “no enclo s ure” re fer to the typ e o f Table K.1 — Typical values o f s tandard uncertainties due to variations in measurement equipment, operating conditions and environmental conditions E s timate Sources o f uncertainty Measuring procedure (speed vari ation s , s tab i l ity o f me a s u rement s ys tem , l atera l tyre p o s ition) Uncer ta i nty i n e qu ip ment (c a l ib - to r, s ou nd me a s u r i ng s ys tem , s p e e d P robability Sensitivity Uncertainty dis tribution coe fficient contribution normal 0,2 dB normal 0,3 dB normal 0,3 dB 0,1 dB (enclosure) 0,2 dB (no enclosure) 0,2 dB (enclosure) 0,1 dB (no enclosure) 0,5 dB (enclosure) 0,5 dB (no enclosure) me a s u ri n g s ys tem) Effect of environmental conditions (after correction for temperature) Background noise from external sources B ackgrou nd noi s e/re fle c tion from the me a s u r i ng veh icle , ge ome tr y o f mic positions a s ym me tric - p a r tl y a s ym me t r ic/p a r tl y no r m a l C o mb i ne d s ta nd a rd u ncer ta i nty The total spread in measurement results expected in this procedure leads to the expanded uncertainties listed in Table K.2 Table K — Typical values for the expanded uncertainty in this document Coverage prob ability E xpanded uncertainty 80 % 95 % 0,7 dB 1,0 dB With rega rd to the tyre u ncer tai nty contribution, δ6 , re fer to I S O/ T S 1 819 -3 for the quantity to i nclude i n th i s c a lc u l ation I f o ther tyre s tha n s p e ci fie d i n I S O/ T S 11 819 -3 are u s e d, th i s quantity ne e d s to b e s p e c i fie d b y the us er f 11 wheeled CPX trailers were used, and measurements were made in both wheel tracks and averaged NO TE T he e s ti m ate s a re e s s enti a l l y b a s e d on a n e xp eri ment rep or te d i n Re erence [ ] , where on l y two - NO TE T he two l a rge s t s ou rce s o f u ncer ta i nty a re the u ncer ta i ntie s i n the me a s u r i n g e qu ipment for s ou nd a nd s p e e d a nd the e ffe c t o f envi ro n menta l cond ition s , m a i n l y wi nd e ffe c ts I t h a s b e en a s s u me d i n th i s c a lc u l ation th at the temp eratu re e ffe c t o n noi s e em i s s ion NO TE 7) 54 from the te s t tyre s i s known T he e ffe c t o f va r i ation s with i n the p opu l atio n o f re ference tyre s i s no t i nclude d i n the c a lc u l ation 7) Thes e uncertainties are es timated in I S O /TS 1 - ; s ee the I ntro ductio n © ISO 2017 – All rights reserved ISO 1 81 9-2 : 01 7(E) K.5 ISO 72 -2 Guide to laboratories on how to express measurement uncertainties K.5 results Repeatability Re fer to I S O - K.5 Reproducibility measurement results K.6 Re fer to I SO fo r es timatio n 72 -2 fo r o f the intra- lab o rato ry s p read in meas urement es timatio n of the inter- lab o rato ry s p read in Uncertainty o f the survey method described in Annex G T he u ncer tai nty o f the s u r vey me tho d, a s de s crib e d i n in Reference [8], is estimated to be: Annex G, according to the procedure described Rep e atabi l ity l i m it r = dB Repro duc ibi l ity l i m it R NO TE = dB T he e s ti m ate s ab ove a re b a s e d on e x p er i ments where the tyre contributio n to u ncer ta i nty i s i nclude d (which is not the case in K.4 ) a nd where o n l y o ne whe el track wa s me a s u re d I f b o th whe el tracks wou ld b e me a s u re d a nd the re s u lts average d , the u ncer ta i nty e s ti m ate s wou ld b e co me lower © ISO 2017 – All rights reserved 55 ISO 1 81 9-2 : 01 7(E) Annex L (informative) Re ference road surface L.1 General When reporting the measured result for a certain road surface, it is common to compare it to some a reference surface This annex contains recommendations regarding the choice of such surfaces, in re ference case, i.e the corresponding results measured on a sur face type which is considered as being order to avoid the use o f very di fferent re ferences A virtual re ference sur face concept was defined in the EU HARMONOISE project (Re ference [13]) which developed a prediction model for predicting noise emission and immission from road and railway tra ffic In this one, a re ference case was defined, including a re ference sur face The sur face was chosen to be an average of a DAC and an SMA surface, each one having a maximum aggregate size of 11 mm and with an age o f at least one year The reason for this choice was that either an SMA or a DAC sur face with approximately 11 mm maximum aggregate size is very common, and rather easy to find, in each o f the European countries Certain corrections were introduced in cases where the 11 mm aggregate size is di fficult to find, enabling maximum aggregates from 10 mm up to 16 mm to be used, plus correction for age This allowed the use in a particular case o f an actual re ference sur face which deviated slightly from the reference, provided corrections were applied to account for the deviations from the ideal and virtual referenced The procedure, including the corrections to bring an actual case to the virtual reference case, is described in some detail in Reference [14] Later, the same concept was taken over by the IMAGINE project and is also the concept used in the European method according to the CNOSSOS project (Re ference [15]) The options in L.2 to L.4 apply L.2 Virtual re ference surface The re ference sur face is a sur face not existing as such in reality, but being considered as an “average” o f a DAC and an SMA sur face with a maximum aggregate size o f 11 mm Ages shorter than one year should be avoided; also the sur face should not be old enough to be subject to ravelling, cracking or other mechanical de fects The virtual re ference case depends strongly on the representativity o f the actual reference surface used in relation to its nominal values When this concept is used the procedure is as specified in a) to d) a) In the series of measurements considered, make sure that at least one surface which is as close in construction and condition to the virtual reference surface as possible is measured (either DAC or SMA; maximum aggregate size shall be between 10 mm and 16 mm, ideally 11 mm; its condition shall be good but not new) b) Use the correction procedure in Reference [14] to determine what the nominal noise level difference (correction Δ Lref) is between the actual re ference used [as identified in L.2 a)] and the virtual reference surface c) Apply this correction to the measured level(s) o f the actual re ference sur face used and use these corrected level(s) as the level(s) representing the virtual reference surface (be careful to use the correct plus or minus sign) 56 © ISO 2017 – All rights reserved ISO 1 81 9-2 : 01 7(E) d) L.3 T he Us i ng the vi r tua l re ference s ur face as a zero re ference level i n de cib el s , a l l o ther s i m i larly me as u re d surfaces can be compared to this one, presented as a difference in noise level compared to the virtual reference surface (i.e a noise reduction) Normalized re ference case re ference s u r face is a fic titiou s defi ne d b y convention T h i s c an, for s ur face on wh ich the level s L CPX for e ach re ference tyre are i n s tance, b e b a s e d on the average re s u lts o f a gre at numb er o f C PX measurements on asphalt concrete surfaces, after which a certain level is decided upon which would repre s ent th i s c as e; corre c te d to the re ference temp erature ° C T he re ference s u r face i s then an average o f a l l s u r face s i nclude d i n the te s t T he norma l i z e d re ference ca s e dep end s s trongly on the s tabi l ity o f the re ference tyre s and acc u rac y i n corre c tion L.4 for temp erature Arbitrary re ference case T he re ference s u r face i s any a rbitrar y s u r face, o ther than ab ove, that the te s ti ng organ i z ation s ele c ts I n th i s c a s e me as u rements are u s e fu l on ly L.5 for comp ari s on s b e twe en the p a r tic u l ar, s ele c te d s u r face s Conclusion The virtual reference case (L.2) has the advantage of being aligned with the HARMONOISE, IMAGINE and CNOSSOS methods for noise prediction, used European-wide As is pointed out in Reference [14], this reference case is also close to references used in the Nord2000 (Reference [12]), as well as in Japanese and US prediction models, which makes it suitable for worldwide use in cases wherever the use of a reference is of interest If this case is used, whenever a noise reduction is calculated, the results are re a s onab ly comp a rable worldwide © ISO 2017 – All rights reserved 57 ISO 1 81 9-2 : 01 7(E) Annex M (informative) Calculation o f close-proximity sound indices I n order to ob tai n a n aggregate (overa l l) level o f ro ad s u r face i n fluence on tra ffic noi s e tyre s and veh icle s , a C PX s ou nd i nde x ( LCPX:I ,v ref L CPX:I ) may b e c a lc u l ate d for a cer ta i n s p e e d vref for a mi x of as follows: = , 50 LCPX:P ,v ref + , 50 LCPX:H,v ref where LCPX:P ,v ref LCPX:H,v ref LCPX:I ,v ref i s the C PX level repre s enti ng l ight veh icle s i n the tra ffic s tre a m at re ference s p e e d de term i ne d u s i ng te s t tyre P (re fer to I S O/ T S 11 819 -3 ; s e e the I ntro duc tion) ; i s the C PX level repre s enti ng he av y veh icle s i n the tra ffic s tre am at re ference s p e e d de term i ne d u s i ng te s t tyre H (re fer to I S O/ TS 1 819 -3 ; s e e the I ntro duc tion) ; i s the C PX i nde x repre s enti ng noi s e The reporting of measured values LCPX:I ,v ref from m i xe d tra ffic at re ference s p e e d L CPX:I ,v ref from l ight a nd he av y veh icle s T h i s i s a h ighway with % l ight veh icle s a nd % he av y veh icle s (8 km/ h a s s u me d) or a mo tor way with 75 % l ight veh icle s a nd % he av y veh icle s (1 km/ h he av y veh icle s a s s u me d) S e e NOTE The CPX index vref have been chosen in order to represent a mix o f l ight a nd he av y tra ffic with e qu a l co ntr ib ution s o f tyre/ro ad noi s e for , vref is optional, but recommended, in order to facilitate the comparison of NOTE The weighting factors used to calculate the app roxi m atel y the c a s e , vref fu r ther L CPX:I ,v ref 12] is not an equivalent level, Leq fo r for a l l veh icle s l ight a nd km/ h for Re ference [ , o f tra ffic noi s e , b ut c a n b e u s e d to n k is to compare a certain surface with a reference surface according to Annex L (L.2), and to present the result as a difference value d i fferent ro ad s u r face s For e xa mp le , i n m a ny c a s e s , the m a i n u s e o f the L CPX:I ,v 58 ref LCPX:I ,v ref a nd the co rre s p o nd i ng i nde x (S PB I ) me a s u re d with I S O 1 19 -1 a re no t nu mer ic a l l y e qu a l © ISO 2017 – All rights reserved ISO 1 81 9-2 : 01 7(E) Annex N (informative) Summary o f measuring and data-processing procedures Figure N.1 and Figure N.2 Figure N.1 f f that in Figure N.2 Figure N.2, together with Formulae (1) to (11), or (C.1) to (C.11) a re flowch ar ts i l lu s trati ng the me as u rement a nd data-pro ce s s i ng pro ce du re s , re s p e c tively i l lu s trate s the mo s t com mon typ e s o typ e s p o s s ible accord i ng to th i s c ument T he order o me a s u rements , a lb eit no t ne ce s s ari ly a l l c a lc u lati ng average s may no t ne ce s s a ri ly b e ; o ther orders are a l s o p o s s ible without ob ta i n i ng s igni fic a ntly d i fferent re s u lts , may b e us e ful as a mo del for maki ng automatic or s emi-automatic data pro ces s i ng by us e o f an onb o ard computeri zed data pro ces s i ng s ys tem NOTE The numbers refer to the corresponding subclauses Figure N.1 — F lowchart , illus trating measurement procedures © ISO 2017 – All rights reserved 59 ISO 1 81 9-2 : 01 7(E) NOTE The numbers refer to the corresponding subclauses Figure N — Flowchart , illus trating the analysis procedures 60 © ISO 2017 – All rights reserved ISO 11819-2:2017(E) Annex O (informative) Example o f test report This annex shows an example o f how a test report may appear An attempt has been made to include most options in it In certain cases, it is possible to remove items from the report which are not mandatory and not applicable to the tested case © ISO 2017 – All rights reserved 61 ISO 1 81 9-2 : 01 7(E) TE ST REPORT FOR ME ASUREMEN T OF TH E INFLUENCE OF ROAD SURFACES ON TRAFFIC NOISE WI TH TH E CLOSE-PROXIM I T Y METHOD General in formation Date and time of measurements: 2009-11-18 Start 09:00; finish 11:25 Organization/operators responsible for measurements: Technical University o f Gdansk (J Ejsmont) and Swedish Road and Transport Research Institute (U Sandberg) Purpose of the measurement: General survey Type o f measuring equipment 4a Test vehicle: One-wheeled trailer towed by car (user designation o f test vehicle: TUG Trailer, Mark III) 4b Test tyres: Re ference tyres P1 and H1 4c Noise measuring system: B&G 5788 system 4d Calibration equipment: B&G type 4157 4e Speed measuring equipment: Metrilogic type 97AB 4f Meteorology equipment: Thermometric type D34 4g Microphones used: Positions and 4h Certification of test vehicle: Refer to TRL report no XXX In formation relating to the location and appearance o f the tes t site 5a Location oftest site: 27,5 km from exit Kaparp on road RV34 running south from Linkoping, Sweden 5b Posted speed limit: 90 km/h 5c Longitudinal gradient: 1:100 5d Crossfall: % 5e Site plan: See enclosed Figure X1 (not shown in this example but assumed to be added in the report) 5f Total measured distance: 300 m 5g Start position: Add GPS data 5h End position: Add GPS data 5i Lateral measurement position on road: Lane 1, le ft wheel track only Information relating to the type and construction o f the tes ted sur face (where available) 6a Type of surface and its design parameters: Single surface dressing, Swedish designation Y1 (12-16) 6b Thickness of surface layer: N.A (thickness o f one layer o f chippings: ≈ 16 mm) 6c Maximum chipping size: 16 mm 6d Residual air voids content: Not measured 6e Sound absorption coefficient according to ISO 13472-1 : Not measured 6f Representative photo of the surface: See Figure X2 (not included in this example) 6g Texture depth (MPD) according to ISO 13473-1 : 1,52 mm 62 © ISO 2017 – All rights reserved ISO 1 81 9-2 : 01 7(E) 6h Work recipe for surface: Not available In formation concerning condition o f the tes ted sur face and environmental factors (i f available) 7a Age of surface and state of maintenance: ye ars , s ign i fica nt r utti ng i n whe el tracks 7b Any special surface treatment: None 7c Any notes regarding the homogeneity of the surface: None 7d Number of days since the latest precipitation: days b e fore me a s urements (s u r face i s no t p orou s) 7e Average air and road surface temperatures over the test section: 22 °C (air) and 28 °C (road) f Tem p erature correction co e f ficien ts u sed: − ,1 for b o th tyre s Tes t tyre and other tes t conditions 8a Test tyres u sed, iden tification o f tyre an d date o f m an u f acture: Tyre P1 , D O T numb er X X X X X X, ma nu fac ture d We ek 011 Tyre H1 , D O T nu mb er Z Z Z Z Z Z , manu fac tu re d We ek 2 011 8b Rubber hardness of the test tyres (no more than three months old) : 64 for P1, 66 for H1 8c Number of runs on which the L CPX is based: runs 8d Reference speed used: 80 km/h 8e Actual measured test speeds as an average over the test section: S e e pri ma r y te s t pro to col s Measured and calculated sound pressure level data 9a LC PX values (at 80 km/h) : L C PX for tyre P1 = L CPX: P1 ,80 = 91,2 dB = LCPX: H1 ,80 = 93,1 dB (at 80 km/h) = 92,2 dB L C PX for tyre H1 9b L C PX: I , 9c Acoustic variability, st, of the surface: , dB for tyre P1 and ,1 d B for tyre H1 9d Expended uncertainty of the L C PX values (estimation for 95 % coverage): , d B for b o th tyre s Others 10 Speed constant, B, used for speed corrections: 30 11 Details of special provisions taken to ensure conformity with ISO 11819-2 : None © ISO 2017 – All rights reserved 63 ISO 1 81 9-2 : 01 7(E) Bibliography [1] C onter M [2] M+P; TÜV Automotive (2000-I) International CPX validation test ISO/TC43/SC1/WG33 1998–2000 By M+P Raadgevende ingenieurs bv (‘s Hertogenbosch, Netherlands) and TÜV Automotive GmbH (Herzogenrath, Germany) Compilation o f Final Report and data files, on CDROM May 2000 [3] M+P; TÜV Automotive (2000-II) International CPX validation test ISO/TC43/SC1/WG33 19982000 — Summary report By M+P Raadgevende ingenieurs bv (‘s Hertogenbosch, Netherlands) and TÜV Automotive GmbH (Herzogenrath, Germany) M+P/TÜV report ISO.95.1.1, May 2000 [4] [5] [6] Proposal for a draft European standard on the characterisation of the acoustic properties of road surfaces -project ROSANNE Deliverable 2.4, 2016 (http://rosanne eu/ ) S andberg U., & E jsmont J.A Keeping reference tyres and other tyres stable with respect to noise emission Proc Euro-Noise, Edinburgh, 2009 H ung W.T., L am Y.K., L eung C.K.R., N g C.F Which is a better metric — road or air temperature — in assessing temperature e ffects on tyre/road noise? Proc o f Acoustics, Hong Kong, 2012 S andberg U., Glaeser K.P., E jsmont J.A., S ch walbe G The influence of tyre wear and ageing on tyre/road noise emission and rolling resistance Report C.D6 o f the SILENCE project, 2009 Available at (viewed 2016-04-06): www.fehrl org/index.php?m=32 &mode= download&id _file= 6134 [7] P hillips S.M., & Abbott P.G Factors a ffecting statistical pass-by measurements Proc InterNoise 2001 , The Hague, 2001, pp 2031–6 [8] An fosso -Lé dé e F., & P ich aud Y Acoustic monitoring of a road network: investigation of the ageing e ffect o f thin layer asphalt 6th Symp. Pavement Surface Characteristics SURF2008, PIARC, Portoroz, 2008 [9] S andberg U Noise emission influence of road surfaces, as measured with the statistical passby and close-proximity methods, using di fferent vehicle classes and di fferent tyres Proc of the Tyre/road Noise Seminar, 1997, Gdansk VTI Konferens 8A, Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden [10] Ronneberger D., & P reuss C Optimum positions of microphones in trailers Proc of the International Tire/road Noise Con ference, 1990, Gothenburg STU Information No 794–1990, Stockholm: Swedish National Board for Industrial and Technical Development Available from the Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden [11] d e Roo F., T elm an J., van B lokl and G., van Leeuwen H., Reubsaet J., van Vliet W.-J Uncertainty o f close proximity (CPX) tyre road noise measurements — Round robin test results Paper No 281, Proceedings of NAG-DAGA 2009, Rotterdam [12] Nord 2000 ( 2006): Acoustic Source Modelling o f Nordic Road Vehicles By Hans Jonasson, SP Swedish National Testing and Research Institute, SP Report 2006:12, Borås, Sweden ISBN 9185303-96-8 ISSN 0284-5172 [13] J onasson H Source modelling o f road vehicles Deliverable of the Harmonoise project, HARMONOISE Technical Report HAR11TR-020614-SP09v8, SP, Boras, Sweden (www.sp se/en/ Sidor/default.aspx) [14] S andberg U The concept of virtual reference pavement for noise prediction and comparison purposes Proc of Inter-Noise, Honolulu, 2006 [15] 64 Anon COMMISSION DIRECTIVE (EU) 2015/996 o f 19 May 2015 establishing common noise assessment methods according to Directive 2002/49/EC of the European Parliament and of the Council Official Journal of the European Union , L 168/1, 1.7.2015 © ISO 2017 – All rights reserved ISO 1 81 9-2 : 01 7(E) [16] An fosso -Lé dé e F., & Kragh J Wind noise influence on close-proximity tyre/road noise measurements with uncovered systems Inter-Noise 2013 September, pp 15–18 [Innsbruck] [17] B ü hlm ann E., & van B lokl and G.J Temperature effects on tyre/road-noise – A review of empirical research Proc of Forum Acusticum , 7–12 September 2014, Krakow 01 [18] ECE Uni form provisions concerning the approval o f tyres with regard to rolling sound emissions and/or to adhesion on wet surfaces and/or to rolling resistance Regulation 117, E/ECE/324/Rev.2/Add.116/Rev.3−E/ECE/TRANS/505/Rev.2/Add.116/Rev.3, 24 February 2014, United Nations, ECE, Geneva [19] L am Y.K., Leung R.C.K., H ung W.T Impact o f Microphone Vibration on Tyre/road Noise Measurement with Close-Proximity (CPX) Method Proceedings of the 5th Cross-strait Many Cities Symposium on Acoustics, 23–24 November, 2012, Hong Kong, pp 143–7 [20] ISO 3911, Wheels and rims for pneumatic tyres — Vocabulary, designation and marking [21] ISO 10844, Acoustics — Specification of test tracks for measuring noise emitted by road vehicles and their tyres [22] ISO 13472-1, Acoustics — Measurement of sound absorption properties of road surfaces in situ — Part 1: Extended surface method [23] ISO 13473-1, Characterization o f pavement texture by use o f surface profiles — Part 1: Determination o f mean profile depth [24] ISO 80000-2, Quantities and units — Part 2: Mathematical signs and symbols to be used in the natural sciences and technology [25] XP S31-145-1, Acoustique — Caractérisation in situ des performances acoustiques des revêtements de chaussées — Mesures du bruit de contact pneumatique/chaussée en continu — Partie 1: Mesure d’expertise © ISO 2017 – All rights reserved 65 ISO 1 81 9-2 : 01 7(E) ICS 7.1 40.3 Price based on 65 pages © ISO 2017 – All rights reserved