BS ISO 8297-1995 Acoustics - Determination of sound power levels of multisource industrial plants for evaluation of sound pressure levels in the environment - Engineering .pdf

1、BRITISH STANDARD BS ISO 8297:1994 Implementation of ISO 8297:1994 Acoustics Determination of sound power levels of multisource industrial plants for evaluation of sound pressure levels in the environment Engineering methodBSISO8297:1994 This British Standard, having been prepared under the direction

2、of the Health and Environmental Sector Board, was published under the authorityof the Standards Boardand comes into effect on 15October1995 BSI 01-2000 The following BSI references relate to the work on this standard: Committee reference EH/1 Draft for comment 88/50073 DC ISBN 0 580 24821 6 Committe

3、es responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee EH/1, Acoustics, upon which the following bodies were represented: Association of Consulting Engineers British Broadcasting Corporation British Occupational Hygiene Society British

4、Telecommunications plc Department of the Environment (Building Research Establishment) Department of Trade and Industry (National Physical Laboratory) Health and Safety Executive Institute of Acoustics Institute of Occupational Hygienists Institute of Sound and Vibration Research Institution of Elec

5、trical Engineers Royal Institute of British Architects Society of Environmental Engineers The following bodies were also represented in the drafting of the standard, through subcommittees and panels: Advanced Manufacturing Technology Research Institute Agricultural Engineers Association British Ceme

6、nt Association British Compressed Air Society British Gas plc British Industrial Truck Association British Steel plc Construction Industry Research and Information Association Department of Trade and Industry (National Engineering Laboratory) Engineering Industries Association Fan Manufacturers Asso

7、ciation Federation of Associations of Specialists and Subcontractors Federation of Manufacturers of Construction Equipment and Cranes Federation of Piling Specialists Federation of the Electronics Industry Hevac Association Institution of Engineering Designers Institution of Mechanical Engineers Rot

8、ating Electrical Machines Association (BEAMA Ltd.) University of Liverpool University of Manchester Amendments issued since publication Amd. No. Date CommentsBSISO8297:1994 BSI 01-2000 i Contents Page Committees responsible Inside front cover National foreword ii Foreword iii Text of ISO 8297 1BSISO

9、8297:1994 ii BSI 01-2000 National foreword This British Standard reproduces verbatim ISO8297:1994and implements it as the UK national standard. This British Standard is published under the direction of the Health and Environment Sector Board whose Technical Committee EH/1, Acoustics, has the respons

10、ibility to: aid enquirers to understand the text; present to the responsible international committee any enquiries on interpretation, or proposals for change, and keep UK interests informed; monitor related international and European developments and promulgate them in the UK. NOTEInternational and

11、European Standards, as well as overseas standards, are available from Customer Services, BSI, 389Chiswick High Road, London W4 4AL. 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. Com

12、pliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, theISO title page, pages ii to iv, pages 1to 8, an inside back coverand abackcover. This standard has been updated

13、 (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.ISO8297:1994(E) ii BSI 01-2000 Contents Page Foreword iii Introduction 1 1 Scope 1 2 Normative references 2 3 Definitions 2 4 Symbols 3 5 Principle of measurement p

14、rocedure 3 6 Acoustic environment 4 7 Instrumentation 4 8 Operating conditions of the plant 5 9 Procedure 5 10 Calculation of sound power levels for evaluating levels in the environment 7 11 Noise sources significantly elevated above the characteristic height of the plant 8 12 Information to be repo

15、rted 8 Annex A (informative) Bibliography Inside back cover Figure 1 General arrangement of measurement positions on the measurement contour around the plant 4 Table 1 Uncertainty inherent in the method 2 Table 2 Corrections for background noise 6 Table 3 Decrease in sound pressure level during free

16、 propagation due to absorption in the air 7ISO8297:1994(E) BSI 01-2000 iii Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO t

17、echnical 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 clos

18、ely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an InternationalStandard requires approval by at least75%

19、of the member bodies casting a vote. International Standard ISO8297was prepared by Technical Committee ISO/TC43, Acoustics, Subcommittee SC1, Noise. Annex A of this International Standard is for information only.iv blankISO8297:1994(E) BSI 01-2000 1 Introduction 0.1 This International Standard speci

20、fies an engineering method for determining the sound power level of multisource industrial plants which is relevant to the assessment of the noise they contribute to points in the environment around the plant. It is based on measuring the sound pressure level on a closed path (measurement contour) s

21、urrounding the plant and determining an appropriate measurement surface. The method is intended to be applied to large industrial plants having multiple noise sources under any specified operating conditions and to other large sources provided that they can be assumed to radiate substantially unifor

22、mly in all horizontal directions. The method described in this International Standard complies with the general recommendations given in ISO2204. 0.2 Data obtained using this International Standard are suitable for the following purposes. a) To calculate the sound pressure level at given points arou

23、nd a plant under specified weather conditions provided that the distance of such points from the geometrical centre of the plant area is at least1,5times the greatest dimension of the plant area (see Figure 1). All individual sources within the plant area are thereby treated as a single point source

24、 at the geometrical centre of the plant. b) To identify industrial areas or particular parts of such areas in terms of their contribution to the sound pressure levels at given points in the environment. c) To compare different sources (complete plants or component installations) in terms of their so

25、und power level. d) To monitor the noise emission of a plant. 1 Scope 1.1 General This International Standard specifies an engineering method (grade2, as defined in ISO2204) for determining the sound power levels of large multisource industrial plants relevant to the evaluation of sound pressure lev

26、els in the environment. These sound power levels may be used in an appropriate prediction model for such an evaluation. The method is limited to large industrial plants with multiple noise sources (a combination of an unspecified number of individual sources) having their main dimensions in the hori

27、zontal plane, and which radiate sound substantially uniformly in all horizontal directions. Unweighted sound pressure levels are measured in octave bands. The results obtained are expressed both in octave-band sound power levels and, if required, in A-weighted sound power levels. 1.2 Type and size o

28、f noise source The method is applicable to industrial areas where most of the equipment operates outdoors, not enclosed by a building, e.g. petrochemical complexes, factories, stone quarries, crushing plants and pithead installations. The method is also applicable when there are moving sources perfo

29、rming cyclic or continuous operations, such as drag lines or cable conveyors, provided that the measurements can be related to at least one cycle of operation. It is applicable to industrial plants in which the largest horizontal dimension of the plant area lies between16m and approximately320m. 1.3

30、 Types of noise This International Standard applies to sources which radiate broad-band noise, narrow-band noise, discrete tones, repetitive impulsive noise and combinations of such components. The procedure given is applicable to steady noise and to non-steady noise provided that it is statisticall

31、y stationary. It is not suitable for measuring isolated bursts of sound energy. The method is best suited for broad-band steady noise. 1.4 Measurement uncertainty The uncertainty inherent in the method due to the layout of the plant depends mainly on the average distance, , between the measurement c

32、ontour and the boundary of the plant, in relation to the square root of the plant area, S p , and is given in Table 1. dISO8297:1994(E) 2 BSI 01-2000 Table 1 Uncertainty inherent in the method These uncertainties arise from spatial variations in the sound pressure levels (averaged over time) at the

33、different measurement positions, owing to the inhomogeneous distribution of sound sources within the plant. They do not include uncertainties due to variations in the noise emissions of the sources over a period of time. NOTE 1In cases where background noise corrections in accordance with 9.5.4 cann

34、ot be applied, the uncertainties may be greater than those given in Table 1. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. A

35、ll standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standar

36、ds. ISO 266:1975, Acoustics Preferred frequencies for measurements. ISO 1996-1:1982, Acoustics Description and measurement of environmental noise Part1:Basic quantities and procedures. ISO 2204:1979, Acoustics Guide to InternationalStandards on the measurement of airborne acoustical noise and evalua

37、tion of its effects on human beings. ISO 3744:1994, Acoustics Determination of sound power levels of noise sources using sound pressure Engineering method in an essentially free field over a reflecting plane. IEC 225:1966, Octave, half-octave and third-octave band filters intended for the analysis o

38、f sound and vibrations. IEC 651:1979, Sound level meters. IEC 804:1985, Integrating-averaging sound level meters. IEC 942:1988, Sound calibrators. 3 Definitions For the purposes of this International Standard, the following definitions apply. (See also Figure 1.) 3.1 sound power level the sound powe

39、r level of the plant which is relevant to the calculation of the sound pressure level in the environment at a position remote from the plant. It is expressed in decibels it is ten times the logarithm to the base10of the ratio of a given sound power to the reference sound power. The reference sound p

40、ower is1pW (10 12W) the width of a restricted frequency band shall be indicated: for example octave-band sound power level, one-third octave-band sound power level, etc. sound power level is denoted by the following symbols according to context: L W(for frequency bands); L WA(for A-weighted sound po

41、wer level). NOTE 2The sound power level of the plant, as determined by this International Standard, may differ from the sum of the sound power levels of the individual sources in the plant. 3.2 sound pressure level, L p ten times the logarithm to the base10of the ratio of the mean-square sound press

42、ure of a sound to the square of the reference sound pressure. It is expressed in decibels. The reference sound pressure is204Pa the width of a restricted frequency band shall be indicated, for example, octave-band sound pressure level, one-third octave-band sound pressure level, etc. 3.3 plant area,

43、 S p the area in which all the sources of the plant are contained. It is expressed in square metres 3.4 measurement area, S m the total area enclosed by the measurement contour. It is expressed in square metres 3.5 measurement distance, d the distance from the measurement position being considered t

44、o the nearest point on the perimeter of the plant area. It is expressed in metres Value of Uncertainty a dB 0,05 0,1 2,5 0,2 0,5 a Expressed as a95% confidence interval for one determination. d/ S p3,0 +3,5 2,0 +2,5 1,5 +2,0 ISO8297:1994(E) BSI 01-2000 3 3.6 distance between measurement positions, D

45、 m the distance between adjacent measurement positions, measured along the measurement contour. It is expressed in metres 3.7 characteristics height of the plant, H the average height of the noise sources within the plant. It is expressed in metres 3.8 equivalent continuous sound pressure level, L e

46、q,T the value of the sound pressure level of a continuous steady sound that within a measurement time interval, T, has the same mean-square sound pressure as the sound under consideration the level of which varies with time. It is expressed in decibels the equivalent continuous sound pressure level

47、over the measurement time interval, T, is given by the following equation: where 4 Symbols Symbols used throughout this International Standard are as follows. 5 Principle of measurement procedure Plot a simply shaped closed path (measurement contour) surrounding the plant area (see 9.1). Measure the

48、 sound pressure level at equidistant microphone positions along the contour and calculate the average sound pressure level. Make corrections for proximity error, microphone directionality and air absorption (steps5, 6and7in clause 10). Calculate an appropriate area for the measurement surface, takin

49、g into account the area enclosed by the contour, the contour length and the microphone height (step4in clause 10), and use this to determine the relevant sound power level. p 0 is the reference sound pressure (= 204Pa); p t is the instantaneous sound pressure of the sound signal, in pascals. d Measurement distance, in metres Average measurement distance, in metres D m Distance between measurement positions (microphone positions), in metres h Microphone height, in metres h k Height of the midpoint of the kth noise source, in metres H Characte