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1、BRITISH STANDARD CONFIRMED APRIL 1993 BS 3045:1981 Method of Expression of physical and subjective magnitudes of sound or noise in air UDC 534.79.081 Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 03:40:37 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 3045:1981 This British Standard, having
2、been prepared under the direction of the Environment and Pollution Standards Committee, was published under the authority of the Executive Board and comes into effect on 27 February 1981 BSI 10-1999 First published November 1958 First revision February 1981 The following BSI references relate to the
3、 work on this standard: Committee reference EPC/1 Draft for comment 80/53667 DC ISBN 0 580 12028 7 Cooperating organizations The Environment and Pollution Standards Committee, under whose direction this British Standard was prepared, consists of representatives from the following: The organizations
4、marked with an asterisk in the above list, together with the following, were directly represented on the Technical Committee entrusted with the preparation of this British Standard: Association of County CouncilsDepartment of the Environment (Water British Gas CorporationEngineering Division includi
5、ng Water Data British Industrial Measuring and Control Unit) Apparatus Manufacturers AssociationElectricity Supply Industry in England and British Railways BoardWales British Steel IndustryEngineering Equipment Users Association* Chemical Industries AssociationGreater London Council Chemical Society
6、Health and Safety Executive* Committee for Environmental ConservationInstitute of Petroleum Confederation of British IndustryMedical Research Council* Consumer Standards Advisory Committee of Ministry of Agriculture, Fisheries and Food BSINational Coal Board* Council of Engineering InstitutionsNatio
7、nal Consumers Council Department of Energy (Energy Technology)National Water Council Department of Industry (Warren SpringScottish Office Laboratory)Society of Chemical Industry Trades Union Congress Association of Consulting EngineersInstitute of Sound attention is especially drawn to the following
8、. The comma has been used throughout as a decimal marker. In British Standards it is current practice to use a full point on the baseline as the decimal marker. Cross-references The reference to ISO 1683, which only appears in 3.1, is of an informative nature only and the lack at present of an equiv
9、alent British Standard therefore does not affect the validity of this standard. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself c
10、onfer immunity from legal obligations. International StandardCorresponding British Standard ISO 31-VIIBS 5775 Specification for quantities, units and symbols Part 7:1979 Acoustics (Identical) ISO/R 226BS 3383:1961 Normal equal-loudness contours for pure tones and normal threshold of hearing under fr
11、ee-field listening conditions (Technically equivalent) Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 4, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. Thi
12、s will be indicated in the amendment table on the inside front cover. Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 03:40:37 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 3045:1981 BSI 10-19991 0 Introduction The loudness level of any sound may be expressed uniquely in accordance with the p
13、rocedure defining the phon scale (BS 661:1969 “Glossary of acoustical terms”, definition 3013). Owing, however, to the arbitrary nature of the phon scale (which is based on a logarithmic sound pressure scale of a standard tone, taking no account of the characteristics of hearing) loudness values exp
14、ressed in phons have to be interpreted by the user on the basis of previously heard sounds of known loudness level. For some purposes, especially to convey to the non-specialist the relative loudness of different sounds, it is preferable to express loudness values in the units of an alternative scal
15、e. This scale, in which the loudness is expressed in sones, is so constructed that the apparent ratio of the loudnesses of two sounds, as judged by normal observers, is given directly by the ratio of the sone values of the sounds. In the present standard the sone scale is specified by its relation t
16、o the phon scale, the relation used being an approximation based on assessments of the available experimental evidence. It does not necessarily represent the degree of accuracy required for research purposes, nor should it be deemed to serve any function other than the conversion of loudness levels
17、in phons to loudness in sones and vice versa. 1 Scope and field of application This British Standard expresses the physical and subjective magnitudes which are used in the description of acoustical sound or noise in air. 2 References ISO 31-7, Quantities and units of acoustics. ISO/R 226, Normal equ
18、al-loudness contours for pure tones and normal threshold of hearing under free field listening conditions. ISO 1683, Acoustics Preferred reference quantities for acoustic levels1). 3 Physical magnitudes of sound or noise 3.1 General It is recommended that data on the physical magnitude of sound or n
19、oise be expressed by a statement of the sound pressure level measured at a particular point (see 3.2) or in terms of the sound power level of a source (see 3.3). Reference quantities for acoustic levels used in this British Standard are in accordance with those of ISO 1683. 3.2 Sound pressure level
20、The sound pressure level, Lp, expressed in decibels, of a sound or noise is given by the formula : where NOTEA-weighting is frequently exployed, yielding a value of the A-weighted sound pressure level in decibels. Other weightings may also be used. 3.3 Sound power level The sound power level, Lw2),
21、expressed in decibels, of a source is given by the formula: where NOTEA-weighting is frequently employed yielding a value of the A-weighted sound power level in decibels. Other weightings may also be used. 3.4 Sound intensity level The sound intensity level, LI, expressed in decibels, of a sound or
22、noise is given by the formula: where 1) At present at the stage of draft. pis the root-mean-square value of sound pressure measured at a particular point; p0is the reference sound pressure (= 20 4Pa). 2) The symbol Lp may also be used. Pis the total sound power emitted by source of sound or noise; P
23、0is the reference sound power (= 1 pW). Iis the sound intensity of the sound field; I0 is the reference sound intensity (= 1 pW/m2). 20 lg p p0 - - 10 lg p p0 - - 10 lg I I0 - - Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 03:40:37 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 3045:1981 2
24、BSI 10-1999 4 Subjective magnitudes of sound or noise 4.1 Loudness level Phon 4.1.1 Loudness level The loudness level, LN, of a sound is expressed as n phon, when it is judged by normal observers to be equally loud to a pure tone of frequency 1 000 Hz consisting of a plane progressive sound wave, co
25、ming from directly in front of the observer, the sound pressure level of which is n dB. NOTEThe measurement conditions should be described. 4.1.2 Phon The phon is a unit with the dimension 1, used to express the loudness level of a given sound or noise. 4.2 Loudness scale Sone 4.2.1 Loudness The lou
26、dness level of any sound may be expressed uniquely in phons in accordance with the procedure defining the phon scale (see 4.1.1). Owing, however, to the arbitrary definition of this scale, loudness level values, in phons, do not immediately convey the magnitude of the loudness sensation, but have to
27、 be interpreted by the user on the basis of his experience of previously heard sounds to which phon values have been attached. The purpose of the sone scale is to provide a numerical designation of the loudness of sounds or noises that is proportional to the subjective magnitude as estimated by norm
28、al observers (see ISO/R 226). This British Standard specifies a function relating the loudness, in sones, of a steady sound or noise to its loudness level, in phons. The relation specified is an approximation of the laboratory data sufficiently accurate for expressing loudness in engineering applica
29、tions. It does not necessarily represent the degree of accuracy required for research purposes. 4.2.2 Sone The sone is a unit with the dimension 1, used to express the magnitude of loudness sensation of a given sound or noise. The loudness, N, in sones, of any sound is given by the formula: where LN
30、 is the loudness level, expressed in phons. The relation between N and LN is given in the table. For the definition of sone and phon, see also ISO 31-7. For practical reasons these two “units” are used as dimensions for quantities with the dimension 1, and the following approximate relation is somet
31、imes used: lg N = 0,03 (LN 40) NOTE 1The specified relation defines the value of the sone (unit of loudness) as the loudness of a sound whose loudness level is 40 phons. NOTE 2A twofold change in loudness corresponds to an interval of 10 phons. NOTE 3Experimental confirmation of this relation exists
32、 over the range 40 to 105 phons, and its use outside this range should be recognized as an extrapolation. 2 0,1 LN40() Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 03:40:37 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 3045:1981 BSI 10-19993 Table Relation between loudness level, LN, in ph
33、ons and loudness, N, in sones LNNLNNLNN phonssonesphonssonesphonssones 200,250552,839032,0 210,268563,039134,3 220,287573,259236,8 230,308583,489339,4 240,330593,739442,2 250,354604,009545,3 260,379614,299648,5 270,406624,599752,0 280,435634,929855,7 290,467645,289959,7 300,500655,6610064,0 310,5366
34、66,0610168,6 320,574676,5010273,5 330,616686,9610378,8 340,660697,4610484,4 350,707708,0010590,5 360,758718,5710697,0 370,812729,19107104 380,871739,85108111 390,9337410,6109119 401,007511,3110128 411,077612,1111137 421,157713,0112147 431,237813,9113158 441,327914,9114169 451,418016,0115181 461,5281
35、17,1116194 471,628218,4117208 481,748319,7118223 491,878421,1119239 502,008522,6120256 512,148624,3 522,308726,0 532,468827,9 542,648929,9 NOTEValues in sones are given to three significant figures for purposes of interpolation only. For use, the values should be rounded to two significant figures.
36、Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 03:40:37 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 4 blank Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 03:40:37 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 3045:1981 BSI 10-1999 Publications referred to See foreword. Licensed Copy:
37、 sheffieldun sheffieldun, na, Wed Nov 29 03:40:37 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 3045:1981 BSI 389 Chiswick High Road London W4 4AL BSI British Standards Institution BSI is the independent national body responsible for preparing British Standards. It presents the UK view on standards
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