1、BRITISH STANDARD BS EN ISO 4869-2:1995 Incorporating amendment no. 1 and corrigendum no. 1 Acoustics Hearing protectors Part 2: Estimation of effective A-weighted sound pressure levels when hearing protectors are worn ICS 13.140; 13.340.20 BS EN ISO 4869-2:1995 This British Standard was published un
2、der the authority of the Standards Board and comes into effect on 15 March 1995 BSI 2007 ISBN 978 0 580 59311 6 National foreword This British Standard is the UK implementation of EN ISO 4869-2:1995, incorporating corrigendum June 2007. It is identical with ISO 4869-2:1994, incorporating corrigendum
3、 September 2006. The UK participation in its preparation was entrusted to Technical Committee EPC/1, Acoustics. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract.
4、Users are responsible for its correct application. Compliance with a British Standard cannot confer immunity from legal obligations. Amendments issued since publication Amd. No. Date Comments 8935 December 1995 Renumbers BS ISO 4869-2:1995 as BS EN ISO 4869-2:1995 17353 Corrigendum No. 1 28 Septembe
5、r 2007 Correction to equation (2) and addition of note to Table 2EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 4869-2 June1995 ICS 13.140 Descriptors: Acoustics, safety devices, hearing protectors, tests, performance tests, acoustic tests, determination, sound pressure, attenuation, rules
6、 of calculation English version Acoustics Hearing protectors Part2: Estimation of effective A-weighted sound pressure levels when hearing protectors are worn (ISO4869-2:1994) Acoustique Protecteurs individuels contre le bruit Partie2: Estimation des niveaux de pression acoustique pondrs A en cas dut
7、ilisation de protecteurs individuels contre le bruit (ISO4869-2:1994) Akustik Gehrschtzer Teil2: Abschtzung der beim Tragen von Gehrschtzern wirksamen A-bewerteten Schalldruckpegel (ISO4869-2:1994) This European Standard was approved by CEN on1995-04-27. CEN members are bound to comply with the CEN/
8、CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to a
9、ny CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions.
10、CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and UnitedKingdom. CEN European Committee for Standardization Comit Europen de Normalisation Eu
11、ropisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1995 All rights of reproduction and communication in any form and by any means reserved in all countries to CEN and its members Ref. No. EN ISO 4869-2:1995E Incorporating corrigendum June 2007 BSI 2007 Foreword The
12、 text of the InternationalStandard from ISO/TC43, Acoustics, of the International Organization for Standardization (ISO) has been taken over as a European Standard by the TechnicalCommittee CEN/TC211, Acoustics. This European Standard shall be given the status ofa national standard, either by public
13、ation of anidentical text or by endorsement, at the latest byDecember1995, and conflicting national standards shall be withdrawn at the latest byDecember1995. This European Standard has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association, and
14、 supports essential requirements ofECDirective(s). According to the CEN/CENELEC Internal Regulations, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal
15、, Spain, Sweden, Switzerland and the UnitedKingdom. EN ISO 4869-2:1995EN ISO 4869-2:1995ii Contents Page Foreword iii Introduction 1 1 Scope 1 2 Normative references 2 3 Definitions 2 4 Measurement of sound attenuation of hearing protectors 3 5 Calculation of the assumed protection value, APV fx , o
16、f a hearing protector for a selected protection performance 3 6 Octave-band method 3 7 HML method 4 8 SNR method 5 Annex A (informative) Example of the calculation of the assumed protection values, APV fx 7 Annex B (informative) Example of the calculation of L Axaccording to the octave-band method 7
17、 Annex C (informative) Example of calculation and use ofH,M andL values 7 Annex D (informative) Example of the calculation and use of SNR values 9 Annex E (informative) Bibliography 9 Table 1 Values of ! for various protection performances x 3 Table 2 A-weighted octave-band sound pressure levels, L
18、Af(k)i , of eight reference noises normalized to an A-weighted sound pressure level of100dB, (L C L A ) values and constants d i 5 Table 3 A-weighted octave-band sound pressure levels, L Af(k) , of a pink noise which has aC-weighted sound pressure level of100dB 6 Table A.1 Calculation of APV f80 7 T
19、able B.1 Calculation of L A80using the octave-band method 7 Table C.1 Calculation of the difference between L Af(k)iandAPV f80 8 Table D.1 Calculation of the difference betweenL Af(k)andAPV f80 9 Descriptors: Acoustics, safety devices, hearing protectors, tests, performance tests, acoustic tests, de
20、termination, sound pressure, attenuation, rules of calculation. BSI 2007 EN ISO 4869-2:1995 BSI 2007 iii Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing InternationalStandards is norma
21、lly 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 th
22、e work. ISO collaborates closely 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 International Standard req
23、uires approval by at least75% of the member bodies casting a vote. International StandardISO4869-2 was prepared by Technical Committee ISO/TC43, Acoustics, SubcommitteeSC1, Noise. ISO4869 consists of the following parts, under the general title Acoustics Hearing protectors: Part 1: Subjective method
24、 for the measurement of sound attenuation; Part 2: Estimation of effective A-weighted sound pressure levels when hearing protectors are worn; Part 3: Simplified method for the measurement of insertion loss of ear-muff type protectors for quality inspection purposes; Technical Report Part 4: Methods
25、for the measurement of sound attenuation of amplitude-sensitive hearing protectors. Annex A,Annex B,Annex C,Annex D andAnnex E of this part ofISO4869 are for information only. EN ISO 4869-2:1995iv blank BSI 2007 1 Introduction Ideally, the A-weighted sound pressure level effective when a hearing pro
26、tector is worn should be estimated on the basis of both the octave-band sound attenuation data of the hearing protector (measured in accordance with ISO4869-1) and the octave-band sound pressure levels of the noise. It is recognized, however, that in many situations information on the octave-band so
27、und pressure levels of the noise might not be available. Therefore, for many practical purposes, there is a need for simpler methods to determine the effective A-weighted sound pressure levels which are only based on theA- andC-weighted sound pressure levels of the noise. This part ofISO4869 address
28、es both of these situations by specifying an octave-band calculation method as well as two alternative simplified procedures, the HML method and theSNR method. The octave-band method is a straightforward calculation method involving the workplace octave-band sound pressure levels and the octave-band
29、 sound attenuation data for the hearing protector which is being assessed. Although it can be thought of as an “exact” reference method, it has its own inherent inaccuracies, since it is based upon mean sound attenuation values and standard deviations and not the specific sound attenuation values fo
30、r the individual person in question. The HML method specifies three attenuation values,H,M andL, determined from the octave-band sound attenuation data of a hearing protector. These values, when combined with theC- andA-weighted sound pressure levels of the noise, are used to calculate the effective
31、 A-weighted sound pressure level when the hearing protector is worn. The SNR method specifies a single attenuation value, the single number rating reduction, determined fromthe octave-band sound attenuation data of a hearing protector. This value is subtracted from the C-weighted sound pressure leve
32、l of the noise to calculate the effective A-weighted sound pressure level when the hearing protector is worn. Due to the large spread of the sound attenuation provided by hearing protectors when worn by individual persons, all three methods are nearly equivalent in their accuracy in the majority of
33、noise situations. Eventhe simplest method, the SNR method, will provide a reasonably accurate estimate of the effective A-weighted sound pressure level to aid in the selection and specification of hearing protectors. In special situations, for example especially high- or low-frequency noises, it may
34、, however, be advantageous to use either the HML or the octave-band method. Depending on the choice of a certain parameter in the calculation process, various protection performances can be obtained. It should be noted that the protection performance values for all three methods are only valid when:
35、 the hearing protectors are worn correctly and in the same manner as they were worn by subjects when carrying out theISO4869-1 test; the hearing protectors are properly maintained; the anatomical characteristics of the subjects involved in theISO4869-1 test are a reasonable match for the population
36、of actual wearers. Thus, the principal source of potential inaccuracy in use of the three methods described in this part ofISO4869 is the basicISO4869-1 input data. If the input data do not accurately describe the degree of protection achieved by the target population, then no calculation method wil
37、l provide sufficient accuracy. NOTE 1Differences of3dB or less in the determination of the effective sound pressure level for comparable hearing protectors are insignificant for the purposes of distinguishing between the hearing protectors. NOTE 2Caution should be exercised to avoid the selection of
38、 hearing protectors which provide unnecessarily high attenuation. Such devices might cause communication difficulties or be less comfortable than ones with lower sound attenuation and therefore they might be worn for less of the time. 1 Scope This part ofISO4869 describes three methods (the octave-b
39、and, HML and SNR methods) of estimating the A-weighted sound pressure levels effective when hearing protectors are worn. The methods are applicable to either the sound pressure level or the equivalent continuous sound pressure level of the noise. Although primarily intended for steady noise exposure
40、s, the methods are also applicable to noises containing impulsive components. These methods are not suitable for use with peak sound pressure level measurements. EN ISO 4869-2:19952 BSI 2007 The octave-band,H,M,L orSNR values are suitable for establishing sound attenuation criteria for selecting or
41、comparing hearing protectors, and/or setting minimum acceptable sound attenuation requirements. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this part ofISO4869. At the time of publication, the editions indicated we
42、re valid. All standards are subject to revision, and parties to agreements based on this part ofISO4869 are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members ofIEC andISO maintain registers of currently valid InternationalStandar
43、ds. ISO 4869-1:1990, Acoustics Hearing protectors Part1: Subjective method for the measurement of sound attenuation. IEC 651:1979, Sound level meters. 3 Definitions For the purposes of this part ofISO4869, the definitions given inISO4869-1 and the following definitions apply. 3.1 protection performa
44、nce the percentage of situations for which the A-weighted sound pressure level effective when the hearing protector is worn is equal to or less than the predicted value the value is designated by adding a subscript to the attenuation values according to the different methods,e.g.H 80 ,M 80 ,L 80 ,SN
45、R 80 NOTE 3The value of protection performance is often chosen to be84% corresponding to the constant! =1 (seeclause5). In this case, the subscripts to the attenuation values may be omitted. NOTE 4A situation is a combination of a particular individual wearing a given hearing protector in a specific
46、 noise environment. 3.2 effective A-weighted sound pressure level, L Ax for a specified protection performance, x, and a specific noise situation, the A-weighted sound pressure level effective when a given hearing protector is worn, calculated in accordance with any of the three methods specified in
47、 this part ofISO4869 3.3 predicted noise level reduction, PNR x for a specified protection performance, x, and a specific noise situation, the difference between the A-weighted sound pressure level of the noise, L A , and the effective A-weighted sound pressure level,L Ax , when a given hearing prot
48、ector is worn 3.4 high-frequency attenuation value, H x for a specified protection performance, x, and a given hearing protector, a value representing the predicted noise level reduction, PNR x , for noises with(L C L A )=2dB 3.5 medium-frequency attenuation value, M x for a specified protection per
49、formance,x, and a given hearing protector, a value representing the predicted noise level reduction, PNR x , for noises with(L C L A )=+2dB 3.6 low-frequency attenuation value,L x for a specified protection performance,x, and a given hearing protector, a value representing the predicted noise level reduction, PNR x , for noises with(L C L A )=+10dB EN ISO 4869-2:1995 BSI 2007 3 3.7 single number rating, SNR x for
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