1、BRITISH STANDARD BS 7445-2: 1991 ISO 1996-2: 1987 Description and measurement of environmental noise Part 2: Guide to the acquisition of data pertinent to land useBS7445-2:1991 This British Standard, having been prepared under the directionof the Environment andPollution Standards Policy Committee,
2、was published underthe authority of the Standards Board and comes intoeffect on 28June1991 BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference EPC/1 Draft for comment 83/54417 DC ISBN 0 580 19736 0 Committees responsible for this British Standard The pre
3、paration of this British Standard was entrusted by the Environment and Pollution Standards Policy Committee (EPC/-) to Technical Committee EPC/1, upon which the following bodies were represented: Association of Consulting Engineers British Broadcasting Corporation British Occupational Hygiene Societ
4、y British Telecommunications plc Department of Health Department of the Environment (Building Research Establishment) Department of Trade and Industry (Air Division) Department of Trade and Industry (National Physical Laboratory) Engineering Equipment and Materials Users Association Health and Safet
5、y Executive Incorporated Association of Architects and Surveyors Institute of Acoustics Institute of Occupational Hygienists Institute of Physics Institute of Sound and Vibration Research Institution of Civil Engineers Institution of Electrical Engineers Royal Institute of British Architects Society
6、 of Environmental Engineers Transmission and Distribution Association (BEAMA Ltd.) The following bodies were also represented in the drafting of the standard, through subcommittees and panels: Association of Consulting Scientists Association of Metropolitan Authorities Association of Noise Consultan
7、ts British Cement Association British Coal Corporation British Forging Industry Association British Gas plc British Steel plc Department of the Environment Electricity Supply Industry in United Kingdom Engineering Industries Association Federation of Civil Engineering Contractors Institution of Envi
8、ronmental Health Officers London Regional Transport Ministry of Defence Petroleum Industry Association Royal Automobile Club University of Salford Amendments issued since publication Amd. No. Date CommentsBS7445-2:1991 BSI 12-1999 i Contents Page Committees responsible Inside front cover National fo
9、reword ii 0 Introduction 1 1 Scope and field of application 1 2 References 1 3 Definitions 1 4 Acquisition of data 1 5 Determination of long-term average sound level and long-term average rating level 2 6 Prediction of noise levels 5 7 Noise zones, representation of results 5 8 Information to be rec
10、orded 6 9 Information to be reported 7 Table 1 5 Table 2 5 Publication(s) referred to Inside back coverBS7445-2:1991 ii BSI 12-1999 National foreword This Part of BS7445 has been prepared under the direction of the Environment and Pollution Standards Policy Committee and is identical with ISO1996-2:
11、1987, “Acoustics Description and measurement of environmental noise Part2:Acquisition of data pertinent to land use,” published by the International Organization for Standardization (ISO). ISO1996-2 was prepared by Subcommittee1, Noise, of ISO Technical Committee43, Acoustics, with the active partic
12、ipation and approval of the UK. BS 7445 at present comprises the following Parts which have been published. Part 1: Guide to quantities and procedures; Part 2: Guide to the acquisition of data pertinent to land use; Part 3: Guide to application to noise limits. A British Standard does not purport to
13、 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 confer immunity from legal obligations. Cross-references International Standard Corresponding British Standard ISO 1996
14、-1:1982 BS 7445 Description and measurement of environmental noise Part 1:1991 Guide to quantities and procedures (Identical) IEC 651:1979 a BS 5969:1981 Specification for sound level meters (Identical) IEC 804:1985 a BS 6698:1986 Specification for integrating-averaging sound level meters (Identical
15、) a International Electrotechnical Commission. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages1 to 8, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be
16、 indicated in the amendment table on the inside front cover.BS7445-2:1991 BSI 12-1999 1 0 Introduction 0.1 ISO 1996 comprises the following three parts: Part 1: Basic quantities and procedures; Part 2: Acquisition of data pertinent to land use; Part 3: Application to noise limits. 0.2 This part of I
17、SO1996 describes methods to be used for measuring and describing environmental noise relevant to general land use. The use of different measuring methods, such as continuous integration, sampling techniques and measurements under selected meteorological conditions, is considered. Calculation methods
18、 or scale model investigations may also be used. This part of ISO1996 does not deal in detail with calculation methods. If, however, such methods are used to obtain data pertinent to land use, it is important that the noise be described in a way that is consistent with the requirements of this part
19、of ISO1996. The purpose of this part of ISO1996 is to provide methods for the acquisition of data for describing environmental noise. Using these data as a basis, authorities may establish a system for selecting the appropriate land use, as far as levels of noise are concerned, for a specified area,
20、 or the sources of noise existing or planned which are acceptable with respect to land use, existing or planned. This part of ISO1996 does not give guidance on the estimation of the overall uncertainty of the results, but this should be considered in each specific case, if possible. It does not spec
21、ify noise limits. 1 Scope and field of application This part of ISO1996 describes methods for the acquisition of data which provide descriptors that enable a) a description of the environmental noise in a specified area of land to be made in a uniform way; b) the compatibility of any land use activi
22、ty or projected activity to be assessed with respect to existing or predicted noise. 2 References ISO 1996-1, Acoustics Description and measurement of environmental noise Part1:Basic quantities and procedures 1) . IEC Publication 651, Sound level meters. IEC Publication 804, Integrating-averaging so
23、und level meters. 3 Definitions For the purposes of this part of ISO1996, the definitions given in ISO1996-1 together with the following definitions apply. 3.1 land use an existing or intended use of a delineated area of land 3.2 noise zone region where the long-term average rating level lies betwee
24、n two specified levels such as, for example, between65 and70dB. The noise zone number for this example is6570dB 3.3 receiver person or group of persons who are or who are expected to be exposed to environmental noise 4 Acquisition of data For the purpose of acquisition of data relevant to land use,
25、the following basic information is required: a) geographical description of the area under consideration; b) description of the main characteristics of the sources of noise pertinent to this area; c) description of the situation of the receiver, such as location, occupation, use and features of the
26、immediate surroundings. NOTEIf possible, information on prevailing meteorological conditions in the area under consideration should be given, preferably as statistical information on wind speed and direction, on precipitation and temperature (including the occurrence of temperature inversions) for a
27、 typical time interval, such as a year or any other suitable time interval. 4.1 Acoustical data 4.1.1 General Basic acoustical data are equivalent continuous A-weighted sound pressure levels determined over the reference time intervals and rating levels for the same reference time intervals with add
28、itional information on the characteristics of the noise, if required. 4.1.2 Rating level The rating level shall be determined over reference time intervals related to the characteristics of the source(s) and receiver(s). 1) Cross-references to specific clauses, sub-clauses, etc. in ISO1996-1 apply t
29、o the first edition published in1982.BS7445-2:1991 2 BSI 12-1999 The rating level, (L Ar,T ) i , for each reference time interval, is given by the formula (L Ar,T ) i= (L Aeq,T ) i + K 1i + K 2i where (L Aeq,T ) i is the equivalent continuous A-weighted sound pressure level during the ith reference
30、time interval; K 1i is a tone adjustment applicable to the ith reference time interval; K 2i is an impulse adjustment applicable to the ith reference time interval. NOTEIf the tone or impulse characteristics are present for only a part of the reference time interval, the values of K 1and K 2may be a
31、djusted to take account of the duration. 4.1.3 Tone adjustment, K 1 If tonal components are essential characteristics of the sound within a specified time interval, an adjustment may be applied, for that time interval, to the measured equivalent continuous A-weighted sound pressure level. The value
32、of this adjustment shall be stated. NOTEIn some practical cases, a prominent tonal component may be detected in one-third octave spectra if the level of a one-third octave band exceeds the level of the adjacent bands by5dB or more, but a narrow-band frequency analysis may be required in order to det
33、ect precisely the occurrence of one or more tonal components in a noise signal. If tonal components are clearly audible and their presence can be detected by a one-third octave analysis, the adjustment may be5 to6dB. If the components are only just detectable by the observer and demonstrated by narr
34、ow-band analysis, an adjustment of2 to3dB may be appropriate. 4.1.4 Impulse adjustment, K 2 If impulse is an essential characteristic of the sound within a specified time interval, an adjustment may be applied, for this time interval, to the measured equivalent continuous A-weighted sound pressure l
35、evel. The value of this adjustment shall be stated. NOTE 1A method of describing the impulse characteristic of the sound within the specified time interval is to measure the difference between the A-weighted sound pressure level, determined with time-weighting characteristicI averaged over the same
36、time interval, andL Aeq,T . The sound pressure levels should be determined simultaneously. The character of the noise may be further illustrated by determining the peak level and the number of impulses during a specified time interval. NOTE 2For large-amplitude noise, such as the noise generated by
37、sonic booms, mining or quarry blasts, measurements with C-weighting are used in some countries to determine the rating level. 4.2 Meteorological adjustment To extrapolate from a value of the equivalent continuous A-weighted sound pressure level measured under selected meteorological conditions to a
38、long-term value, a meteorological adjustment may be used (see5.3 in ISO1996-1). 4.3 Long-term average sound level The long-term average sound level, L Aeq,LT , in decibels, for a given reference time interval, is given by the following formula: where N is the number of samples of the reference time
39、interval; (L Aeq,T ) i is the equivalent continuous A-weighted sound pressure level in the ith sample, in decibels. 4.4 Long-term average rating level The long-term average rating level, L Ar,LT , in decibels, for a given reference time interval, is given by the following formula: where N is the num
40、ber of samples of the reference time interval; (L Ar,T ) i is the rating level in the ith sample, in decibels. 4.5 Percentile level In some cases, it may be desirable to describe a noise situation by the use of both the equivalent continuous A-weighted sound pressure level and the distribution of A-
41、weighted sound pressure levels. For this purpose, percentile levels such as L 95 , L 50andL 5may be determined. 5 Determination of long-term average sound level and long-term average rating level 5.1 General In general, these quantities are determined from measurements and/or calculations. The resul
42、ts shall be representative of the sound pressure level at a specified location. The measurement technique used, for example the instrumentation, the number of microphone positions, the number and duration of measurement time intervals, depends on the nature of the sound sources and the receivers, an
43、d on the significance of the results for land use. Results that include contributions from exceptional sounds that are not typical for the noise received at a specified location shall be stated separately, if necessary.BS7445-2:1991 BSI 12-1999 3 5.2 Instrumentation See clause4 in ISO1996-1. The ins
44、trument used shall comply with the specifications for sound level meters, preferably oftype1, but at least of type2, given in IECPublication651. Integrating-averaging soundlevel meters shall be as specified in IECPublication804. If a recording device (e.g. a tape recorder, digital recorder,etc.) is
45、used, its effect on the accuracy of the measurements shall be taken into account. 5.3 Location and number of measurement positions 5.3.1 General The measurement of equivalent continuous A-weighted sound pressure levels shall be carried out at those outdoor locations that are appropriate for the acou
46、stical description of the environment under consideration. The measurement positions shall be indicated on a map. The location and number of measurement positions will depend on the required spatial resolution for the environment under consideration. The measurement positions may be a) chosen at app
47、roximately equally spaced positions over the area under consideration (e.g.at the intersections of grid lines on themap) contours of equal levels of noise can be drawn by interpolation between the points; b) representative of the average level of a specified zone or area (e.g.taking into account loc
48、al shielding effects, topographical features,etc.); c) at locations which characterize the noise which results from emissions by various sources that can be identified in the area under consideration; this allows noise to be determined at other locations in the area by means of calculations based on
49、 the propagation of sound. 5.3.2 Microphone position The height of the microphone shall be chosen according to the actual or expected height of the receiver. In potentially built-up areas, the preferred measurement height shall be3 to11m. In all other cases, see5.2.1 in ISO1996-1. NOTEBy choosing the greater measurement height, the influence of ground effects and low barriers is reduced and the reproducibility is improved, but the measured level will generally be higher than that measured close to the ground. In the case of outdoor measurements near bui
